diff --git a/packages/cli/create-strapi-app/index.js b/packages/cli/create-strapi-app/index.js
index ef3a3ce78e2..7f34f0f3f25 100755
--- a/packages/cli/create-strapi-app/index.js
+++ b/packages/cli/create-strapi-app/index.js
@@ -1,4 +1,5 @@
 #!/usr/bin/env node
+
 'use strict';
 
 require('./create-strapi-app');
diff --git a/packages/cli/create-strapi-starter/index.js b/packages/cli/create-strapi-starter/index.js
index 01bfe1deeee..3f4347847ef 100755
--- a/packages/cli/create-strapi-starter/index.js
+++ b/packages/cli/create-strapi-starter/index.js
@@ -1,4 +1,5 @@
 #!/usr/bin/env node
+
 'use strict';
 
 require('./create-strapi-starter');
diff --git a/packages/cli/create-strapi-starter/utils/child-process.js b/packages/cli/create-strapi-starter/utils/child-process.js
index 9ba241e5dff..bc532bbd5e3 100644
--- a/packages/cli/create-strapi-starter/utils/child-process.js
+++ b/packages/cli/create-strapi-starter/utils/child-process.js
@@ -27,12 +27,11 @@ function runApp(rootPath, { useYarn } = {}) {
       stdio: 'inherit',
       cwd: rootPath,
     });
-  } else {
-    return execa('npm', ['run', 'develop'], {
-      stdio: 'inherit',
-      cwd: rootPath,
-    });
   }
+  return execa('npm', ['run', 'develop'], {
+    stdio: 'inherit',
+    cwd: rootPath,
+  });
 }
 
 async function initGit(rootPath) {
diff --git a/packages/cli/create-strapi-starter/utils/stop-process.js b/packages/cli/create-strapi-starter/utils/stop-process.js
index af8137f61be..e2f3360057f 100644
--- a/packages/cli/create-strapi-starter/utils/stop-process.js
+++ b/packages/cli/create-strapi-starter/utils/stop-process.js
@@ -1,4 +1,5 @@
 'use strict';
+
 const logger = require('./logger');
 
 module.exports = function stopProcess(message) {
diff --git a/packages/core/admin/ee/server/controllers/role.js b/packages/core/admin/ee/server/controllers/role.js
index 788a3a2abc0..5c98e20fa4b 100644
--- a/packages/core/admin/ee/server/controllers/role.js
+++ b/packages/core/admin/ee/server/controllers/role.js
@@ -6,7 +6,7 @@ const {
   validateRoleDeleteInput,
   validateRolesDeleteInput,
 } = require('../validation/role');
-const { getService } = require('../../../server//utils');
+const { getService } = require('../../../server/utils');
 const { validatedUpdatePermissionsInput } = require('../validation/permission');
 const { SUPER_ADMIN_CODE } = require('../../../server/services/constants');
 
diff --git a/packages/core/admin/server/domain/action/__tests__/action-domain.test.js b/packages/core/admin/server/domain/action/__tests__/action-domain.test.js
index c2f72977981..90668b17b3d 100644
--- a/packages/core/admin/server/domain/action/__tests__/action-domain.test.js
+++ b/packages/core/admin/server/domain/action/__tests__/action-domain.test.js
@@ -1,6 +1,6 @@
 'use strict';
 
-const domain = require('../');
+const domain = require('..');
 
 describe('Action Domain', () => {
   describe('appliesToProperty', () => {
diff --git a/packages/core/admin/server/domain/action/__tests__/action-provider.test.js b/packages/core/admin/server/domain/action/__tests__/action-provider.test.js
index a8aee66c227..aa9d140e561 100644
--- a/packages/core/admin/server/domain/action/__tests__/action-provider.test.js
+++ b/packages/core/admin/server/domain/action/__tests__/action-provider.test.js
@@ -2,7 +2,7 @@
 
 const { omit } = require('lodash/fp');
 const createActionProvider = require('../provider');
-const domain = require('../');
+const domain = require('..');
 
 const providerMethods = [
   'register',
diff --git a/packages/core/admin/server/domain/condition/__tests__/condition-domain.test.js b/packages/core/admin/server/domain/condition/__tests__/condition-domain.test.js
index 29b328cf4d9..080a1126a36 100644
--- a/packages/core/admin/server/domain/condition/__tests__/condition-domain.test.js
+++ b/packages/core/admin/server/domain/condition/__tests__/condition-domain.test.js
@@ -1,6 +1,6 @@
 'use strict';
 
-const domain = require('../');
+const domain = require('..');
 
 describe('Condition Domain', () => {
   describe('assignConditionId', () => {
diff --git a/packages/core/admin/server/domain/condition/__tests__/condition-provider.test.js b/packages/core/admin/server/domain/condition/__tests__/condition-provider.test.js
index 7a7c74b9c4b..3294ed47ac1 100644
--- a/packages/core/admin/server/domain/condition/__tests__/condition-provider.test.js
+++ b/packages/core/admin/server/domain/condition/__tests__/condition-provider.test.js
@@ -2,7 +2,7 @@
 
 const { omit } = require('lodash/fp');
 const createConditionProvider = require('../provider');
-const domain = require('../');
+const domain = require('..');
 
 const providerMethods = [
   'register',
diff --git a/packages/core/admin/server/domain/condition/provider.js b/packages/core/admin/server/domain/condition/provider.js
index ea5f1f82208..5275071cf9c 100644
--- a/packages/core/admin/server/domain/condition/provider.js
+++ b/packages/core/admin/server/domain/condition/provider.js
@@ -1,7 +1,7 @@
 'use strict';
 
 const { providerFactory } = require('@strapi/utils');
-const domain = require('./');
+const domain = require('.');
 
 /**
  * @typedef ConditionProviderOverride
diff --git a/packages/core/admin/server/domain/permission/__tests__/permission-domain.test.js b/packages/core/admin/server/domain/permission/__tests__/permission-domain.test.js
index 0ad65482855..88c52001a2b 100644
--- a/packages/core/admin/server/domain/permission/__tests__/permission-domain.test.js
+++ b/packages/core/admin/server/domain/permission/__tests__/permission-domain.test.js
@@ -1,6 +1,6 @@
 'use strict';
 
-const domain = require('../');
+const domain = require('..');
 
 describe('Permission Domain', () => {
   describe('addCondition', () => {
diff --git a/packages/core/admin/server/routes/serve-admin-panel.js b/packages/core/admin/server/routes/serve-admin-panel.js
index 1b225b36a4f..3111f5760ff 100644
--- a/packages/core/admin/server/routes/serve-admin-panel.js
+++ b/packages/core/admin/server/routes/serve-admin-panel.js
@@ -23,7 +23,7 @@ const registerAdminPanelRoute = ({ strapi }) => {
     }
 
     ctx.type = 'html';
-    ctx.body = fse.createReadStream(join(buildDir + '/index.html'));
+    ctx.body = fse.createReadStream(join(`${buildDir}/index.html`));
   };
 
   strapi.server.routes([
diff --git a/packages/core/admin/server/services/role.js b/packages/core/admin/server/services/role.js
index 6059f5b78d6..a8012a6ae42 100644
--- a/packages/core/admin/server/services/role.js
+++ b/packages/core/admin/server/services/role.js
@@ -109,7 +109,7 @@ const find = (params = {}, populate) => {
  */
 const findAllWithUsersCount = async populate => {
   const roles = await strapi.query('admin::role').findMany({ populate });
-  for (let role of roles) {
+  for (const role of roles) {
     role.usersCount = await getUsersCount(role.id);
   }
 
@@ -171,7 +171,7 @@ const checkRolesIdForDeletion = async (ids = []) => {
     throw new ApplicationError('You cannot delete the super admin role');
   }
 
-  for (let roleId of ids) {
+  for (const roleId of ids) {
     const usersCount = await getUsersCount(roleId);
     if (usersCount !== 0) {
       throw new ApplicationError('Some roles are still assigned to some users');
diff --git a/packages/core/admin/server/tests/admin-auth.test.e2e.js b/packages/core/admin/server/tests/admin-auth.test.e2e.js
index 0fdc5ffdd77..4678e48af37 100644
--- a/packages/core/admin/server/tests/admin-auth.test.e2e.js
+++ b/packages/core/admin/server/tests/admin-auth.test.e2e.js
@@ -7,7 +7,7 @@ const { createUtils } = require('../../../../../test/helpers/utils');
 
 const edition = process.env.STRAPI_DISABLE_EE === 'true' ? 'CE' : 'EE';
 
-let internals = {
+const internals = {
   role: null,
 };
 
diff --git a/packages/core/admin/server/tests/admin-permission.test.e2e.js b/packages/core/admin/server/tests/admin-permission.test.e2e.js
index b4fe3bd85ad..e9ca0933b6d 100644
--- a/packages/core/admin/server/tests/admin-permission.test.e2e.js
+++ b/packages/core/admin/server/tests/admin-permission.test.e2e.js
@@ -21,7 +21,7 @@ describe('Role CRUD End to End', () => {
   });
 
   test('Can get the existing permissions', async () => {
-    let res = await rq({
+    const res = await rq({
       url: '/admin/permissions',
       method: 'GET',
     });
diff --git a/packages/core/admin/server/tests/admin-permissions-conditions.test.e2e.js b/packages/core/admin/server/tests/admin-permissions-conditions.test.e2e.js
index f0280381ebc..8b510784490 100644
--- a/packages/core/admin/server/tests/admin-permissions-conditions.test.e2e.js
+++ b/packages/core/admin/server/tests/admin-permissions-conditions.test.e2e.js
@@ -13,7 +13,7 @@ if (edition === 'EE') {
     let strapi;
     let utils;
     const builder = createTestBuilder();
-    let requests = {
+    const requests = {
       public: null,
       admin: null,
     };
diff --git a/packages/core/admin/server/tests/admin-role.test.e2e.js b/packages/core/admin/server/tests/admin-role.test.e2e.js
index b2ffb6e4d2c..178666064d1 100644
--- a/packages/core/admin/server/tests/admin-role.test.e2e.js
+++ b/packages/core/admin/server/tests/admin-role.test.e2e.js
@@ -255,7 +255,7 @@ describe('Role CRUD End to End', () => {
       ];
 
       test.each(rolesToCreate)('can create %p', async role => {
-        let res = await rq({
+        const res = await rq({
           url: '/admin/roles',
           method: 'POST',
           body: role,
@@ -465,7 +465,7 @@ describe('Role CRUD End to End', () => {
             },
           });
 
-          for (let role of roles) {
+          for (const role of roles) {
             res = await rq({
               url: `/admin/roles/${role.id}`,
               method: 'GET',
@@ -506,7 +506,7 @@ describe('Role CRUD End to End', () => {
           expect(res.statusCode).toBe(200);
           expect(res.body.data).toMatchObject(roles);
 
-          for (let roleId of rolesIds) {
+          for (const roleId of rolesIds) {
             res = await rq({
               url: `/admin/roles/${roleId}`,
               method: 'GET',
diff --git a/packages/core/admin/server/tests/admin-user.test.e2e.js b/packages/core/admin/server/tests/admin-user.test.e2e.js
index f1d037b902a..bc7e0fc17a9 100644
--- a/packages/core/admin/server/tests/admin-user.test.e2e.js
+++ b/packages/core/admin/server/tests/admin-user.test.e2e.js
@@ -39,7 +39,7 @@ describe('Admin User CRUD (e2e)', () => {
   let strapi;
 
   // Local test data used across the test suite
-  let testData = {
+  const testData = {
     firstSuperAdminUser: undefined,
     otherSuperAdminUsers: [],
     user: undefined,
diff --git a/packages/core/admin/server/validation/common-functions/check-fields-are-correctly-nested.js b/packages/core/admin/server/validation/common-functions/check-fields-are-correctly-nested.js
index 06af0849320..fbb61501df6 100644
--- a/packages/core/admin/server/validation/common-functions/check-fields-are-correctly-nested.js
+++ b/packages/core/admin/server/validation/common-functions/check-fields-are-correctly-nested.js
@@ -6,7 +6,8 @@ const checkFieldsAreCorrectlyNested = fields => {
   if (_.isNil(fields)) {
     // Only check if the fields exist
     return true;
-  } else if (!Array.isArray(fields)) {
+  }
+  if (!Array.isArray(fields)) {
     return false;
   }
 
diff --git a/packages/core/admin/server/validation/common-functions/check-fields-dont-have-duplicates.js b/packages/core/admin/server/validation/common-functions/check-fields-dont-have-duplicates.js
index 8c4a2528146..cce295e8155 100644
--- a/packages/core/admin/server/validation/common-functions/check-fields-dont-have-duplicates.js
+++ b/packages/core/admin/server/validation/common-functions/check-fields-dont-have-duplicates.js
@@ -6,7 +6,8 @@ const checkFieldsDontHaveDuplicates = fields => {
   if (_.isNil(fields)) {
     // Only check if the fields exist
     return true;
-  } else if (!Array.isArray(fields)) {
+  }
+  if (!Array.isArray(fields)) {
     return false;
   }
 
diff --git a/packages/core/admin/webpack.config.dev.js b/packages/core/admin/webpack.config.dev.js
index 02581169d03..74a7b1dc3f4 100644
--- a/packages/core/admin/webpack.config.dev.js
+++ b/packages/core/admin/webpack.config.dev.js
@@ -1,7 +1,7 @@
 'use strict';
 
 const path = require('path');
-const BundleAnalyzerPlugin = require('webpack-bundle-analyzer').BundleAnalyzerPlugin;
+const { BundleAnalyzerPlugin } = require('webpack-bundle-analyzer');
 const { DuplicateReporterPlugin } = require('duplicate-dependencies-webpack-plugin');
 const getPluginsPath = require('./utils/get-plugins-path');
 const webpackConfig = require('./webpack.config');
diff --git a/packages/core/admin/webpack.config.js b/packages/core/admin/webpack.config.js
index 96cdabf5d82..e105adc651c 100644
--- a/packages/core/admin/webpack.config.js
+++ b/packages/core/admin/webpack.config.js
@@ -56,7 +56,7 @@ module.exports = ({
 
   return {
     mode: isProduction ? 'production' : 'development',
-    bail: isProduction ? true : false,
+    bail: !!isProduction,
     devtool: isProduction ? false : 'eval-source-map',
     experiments: {
       topLevelAwait: true,
diff --git a/packages/core/content-manager/server/services/utils/configuration/layouts.js b/packages/core/content-manager/server/services/utils/configuration/layouts.js
index 27188370a40..4628ccafe97 100644
--- a/packages/core/content-manager/server/services/utils/configuration/layouts.js
+++ b/packages/core/content-manager/server/services/utils/configuration/layouts.js
@@ -79,12 +79,12 @@ function syncLayouts(configuration, schema) {
 
   let cleanEditRelations = editRelations.filter(attr => hasRelationAttribute(schema, attr));
 
-  let elementsToReAppend = [];
+  const elementsToReAppend = [];
   let cleanEdit = [];
-  for (let row of edit) {
-    let newRow = [];
+  for (const row of edit) {
+    const newRow = [];
 
-    for (let el of row) {
+    for (const el of row) {
       if (!hasEditableAttribute(schema, el.name)) continue;
 
       /* if the type of a field was changed (ex: string -> json) or a new field was added in the schema
@@ -153,11 +153,11 @@ const appendToEditLayout = (layout = [], keysToAppend, schema) => {
     layout[currentRowIndex] = [];
   }
 
-  for (let key of keysToAppend) {
+  for (const key of keysToAppend) {
     const attribute = schema.attributes[key];
 
     const attributeSize = getDefaultFieldSize(attribute.type);
-    let currenRowSize = rowSize(layout[currentRowIndex]);
+    const currenRowSize = rowSize(layout[currentRowIndex]);
 
     if (currenRowSize + attributeSize > MAX_ROW_SIZE) {
       currentRowIndex += 1;
diff --git a/packages/core/content-manager/server/services/utils/configuration/metadatas.js b/packages/core/content-manager/server/services/utils/configuration/metadatas.js
index 03227d73fa4..efeeabc4b7a 100644
--- a/packages/core/content-manager/server/services/utils/configuration/metadatas.js
+++ b/packages/core/content-manager/server/services/utils/configuration/metadatas.js
@@ -91,7 +91,7 @@ async function syncMetadatas(configuration, schema) {
     const { edit, list } = metasWithDefaults[key];
     const attr = schema.attributes[key];
 
-    let updatedMeta = { edit, list };
+    const updatedMeta = { edit, list };
     // update sortable attr
     if (list.sortable && !isSortable(schema, key)) {
       _.set(updatedMeta, ['list', 'sortable'], false);
diff --git a/packages/core/content-manager/server/tests/api/basic-compo-repeatable.test.e2e.js b/packages/core/content-manager/server/tests/api/basic-compo-repeatable.test.e2e.js
index 04073f729ce..456c7915ba8 100644
--- a/packages/core/content-manager/server/tests/api/basic-compo-repeatable.test.e2e.js
+++ b/packages/core/content-manager/server/tests/api/basic-compo-repeatable.test.e2e.js
@@ -7,7 +7,7 @@ const { createAuthRequest } = require('../../../../../../test/helpers/request');
 const builder = createTestBuilder();
 let strapi;
 let rq;
-let data = {
+const data = {
   productsWithCompo: [],
 };
 
diff --git a/packages/core/content-manager/server/tests/api/basic-compo.test.e2e.js b/packages/core/content-manager/server/tests/api/basic-compo.test.e2e.js
index 139756d0ea9..3af2222038f 100644
--- a/packages/core/content-manager/server/tests/api/basic-compo.test.e2e.js
+++ b/packages/core/content-manager/server/tests/api/basic-compo.test.e2e.js
@@ -7,7 +7,7 @@ const { createAuthRequest } = require('../../../../../../test/helpers/request');
 const builder = createTestBuilder();
 let strapi;
 let rq;
-let data = {
+const data = {
   productsWithCompo: [],
 };
 
diff --git a/packages/core/content-manager/server/tests/api/basic-dp-compo-repeatable.test.e2e.js b/packages/core/content-manager/server/tests/api/basic-dp-compo-repeatable.test.e2e.js
index 0f81ce5aaba..1429a43d4d2 100644
--- a/packages/core/content-manager/server/tests/api/basic-dp-compo-repeatable.test.e2e.js
+++ b/packages/core/content-manager/server/tests/api/basic-dp-compo-repeatable.test.e2e.js
@@ -9,7 +9,7 @@ const { createAuthRequest } = require('../../../../../../test/helpers/request');
 const builder = createTestBuilder();
 let strapi;
 let rq;
-let data = {
+const data = {
   productsWithCompoAndDP: [],
 };
 
diff --git a/packages/core/content-manager/server/tests/api/basic-dp-compo.test.e2e.js b/packages/core/content-manager/server/tests/api/basic-dp-compo.test.e2e.js
index 7c6f16f7e1a..133ecf05b4a 100644
--- a/packages/core/content-manager/server/tests/api/basic-dp-compo.test.e2e.js
+++ b/packages/core/content-manager/server/tests/api/basic-dp-compo.test.e2e.js
@@ -9,7 +9,7 @@ const { createAuthRequest } = require('../../../../../../test/helpers/request');
 const builder = createTestBuilder();
 let strapi;
 let rq;
-let data = {
+const data = {
   productsWithCompoAndDP: [],
 };
 
diff --git a/packages/core/content-manager/server/tests/api/basic-dp-dz.test.e2e.js b/packages/core/content-manager/server/tests/api/basic-dp-dz.test.e2e.js
index a8e2e61f79f..d3c267290a9 100644
--- a/packages/core/content-manager/server/tests/api/basic-dp-dz.test.e2e.js
+++ b/packages/core/content-manager/server/tests/api/basic-dp-dz.test.e2e.js
@@ -9,7 +9,7 @@ const { createAuthRequest } = require('../../../../../../test/helpers/request');
 const builder = createTestBuilder();
 let strapi;
 let rq;
-let data = {
+const data = {
   productsWithDzAndDP: [],
 };
 
diff --git a/packages/core/content-manager/server/tests/api/basic-dp.test.e2e.js b/packages/core/content-manager/server/tests/api/basic-dp.test.e2e.js
index 4c61c19bcb0..26950f87f9f 100644
--- a/packages/core/content-manager/server/tests/api/basic-dp.test.e2e.js
+++ b/packages/core/content-manager/server/tests/api/basic-dp.test.e2e.js
@@ -9,7 +9,7 @@ const { createAuthRequest } = require('../../../../../../test/helpers/request');
 const builder = createTestBuilder();
 let strapi;
 let rq;
-let data = {
+const data = {
   productsWithDP: [],
 };
 
@@ -161,7 +161,7 @@ describe('CM API - Basic + draftAndPublish', () => {
   test('Publish a product, expect publishedAt to be defined', async () => {
     const entry = data.productsWithDP[0];
 
-    let { body } = await rq({
+    const { body } = await rq({
       url: `/content-manager/collection-types/api::product-with-dp.product-with-dp/${entry.id}/actions/publish`,
       method: 'POST',
     });
@@ -174,7 +174,7 @@ describe('CM API - Basic + draftAndPublish', () => {
   test('Publish article1, expect article1 to be already published', async () => {
     const entry = data.productsWithDP[0];
 
-    let { body } = await rq({
+    const { body } = await rq({
       url: `/content-manager/collection-types/api::product-with-dp.product-with-dp/${entry.id}/actions/publish`,
       method: 'POST',
     });
@@ -193,7 +193,7 @@ describe('CM API - Basic + draftAndPublish', () => {
   test('Unpublish article1, expect article1 to be set to null', async () => {
     const entry = data.productsWithDP[0];
 
-    let { body } = await rq({
+    const { body } = await rq({
       url: `/content-manager/collection-types/api::product-with-dp.product-with-dp/${entry.id}/actions/unpublish`,
       method: 'POST',
     });
@@ -206,7 +206,7 @@ describe('CM API - Basic + draftAndPublish', () => {
   test('Unpublish article1, expect article1 to already be a draft', async () => {
     const entry = data.productsWithDP[0];
 
-    let { body } = await rq({
+    const { body } = await rq({
       url: `/content-manager/collection-types/api::product-with-dp.product-with-dp/${entry.id}/actions/unpublish`,
       method: 'POST',
     });
diff --git a/packages/core/content-manager/server/tests/api/basic-dz.test.e2e.js b/packages/core/content-manager/server/tests/api/basic-dz.test.e2e.js
index 532d4c5315b..e41469972e4 100644
--- a/packages/core/content-manager/server/tests/api/basic-dz.test.e2e.js
+++ b/packages/core/content-manager/server/tests/api/basic-dz.test.e2e.js
@@ -7,7 +7,7 @@ const { createAuthRequest } = require('../../../../../../test/helpers/request');
 const builder = createTestBuilder();
 let strapi;
 let rq;
-let data = {
+const data = {
   productsWithDz: [],
 };
 
diff --git a/packages/core/content-manager/server/tests/api/basic-relations.test.e2e.js b/packages/core/content-manager/server/tests/api/basic-relations.test.e2e.js
index df6b628767b..9e212122b3f 100644
--- a/packages/core/content-manager/server/tests/api/basic-relations.test.e2e.js
+++ b/packages/core/content-manager/server/tests/api/basic-relations.test.e2e.js
@@ -8,7 +8,7 @@ let strapi;
 let rq;
 const builder = createTestBuilder();
 
-let data = {
+const data = {
   stamps: [],
   collectors: [],
 };
diff --git a/packages/core/content-manager/server/tests/api/basic.test.e2e.js b/packages/core/content-manager/server/tests/api/basic.test.e2e.js
index 7258c037a1f..5f38eaa7686 100644
--- a/packages/core/content-manager/server/tests/api/basic.test.e2e.js
+++ b/packages/core/content-manager/server/tests/api/basic.test.e2e.js
@@ -9,7 +9,7 @@ const { createAuthRequest } = require('../../../../../../test/helpers/request');
 const builder = createTestBuilder();
 let strapi;
 let rq;
-let data = {
+const data = {
   products: [],
 };
 
diff --git a/packages/core/content-manager/server/tests/api/populate-dz.test.e2e.js b/packages/core/content-manager/server/tests/api/populate-dz.test.e2e.js
index 3f2fe7ab134..e0e8bb37f74 100644
--- a/packages/core/content-manager/server/tests/api/populate-dz.test.e2e.js
+++ b/packages/core/content-manager/server/tests/api/populate-dz.test.e2e.js
@@ -7,7 +7,7 @@ const { createAuthRequest } = require('../../../../../../test/helpers/request');
 const builder = createTestBuilder();
 let strapi;
 let rq;
-let data = {
+const data = {
   productsWithDz: [],
   categories: [],
 };
diff --git a/packages/core/content-manager/server/tests/api/x-to-many-rf-preview.test.e2e.js b/packages/core/content-manager/server/tests/api/x-to-many-rf-preview.test.e2e.js
index 8c48fdc49cf..19d7a437a00 100644
--- a/packages/core/content-manager/server/tests/api/x-to-many-rf-preview.test.e2e.js
+++ b/packages/core/content-manager/server/tests/api/x-to-many-rf-preview.test.e2e.js
@@ -168,7 +168,7 @@ describe('x-to-many RF Preview', () => {
   describe('Relation Nature', () => {
     test(`Throws if the relation's nature is not a x-to-many`, async () => {
       const url = getCMPrefixUrl(categoryModel.singularName);
-      const id = data.category[0].id;
+      const { id } = data.category[0];
 
       const { body, statusCode } = await rq.get(`${url}/${id}/product`);
 
diff --git a/packages/core/content-manager/server/tests/content-manager/uid.test.e2e.js b/packages/core/content-manager/server/tests/content-manager/uid.test.e2e.js
index 8be18276e1f..0815ab71286 100644
--- a/packages/core/content-manager/server/tests/content-manager/uid.test.e2e.js
+++ b/packages/core/content-manager/server/tests/content-manager/uid.test.e2e.js
@@ -8,7 +8,7 @@ const { createAuthRequest } = require('../../../../../../test/helpers/request');
 const builder = createTestBuilder();
 let strapi;
 let rq;
-let uid = 'api::uid-model.uid-model';
+const uid = 'api::uid-model.uid-model';
 
 const model = {
   kind: 'collectionType',
diff --git a/packages/core/content-manager/server/tests/fields/boolean.test.e2e.js b/packages/core/content-manager/server/tests/fields/boolean.test.e2e.js
index 4ce47dc3475..44bb1f4429e 100644
--- a/packages/core/content-manager/server/tests/fields/boolean.test.e2e.js
+++ b/packages/core/content-manager/server/tests/fields/boolean.test.e2e.js
@@ -46,7 +46,7 @@ describe('Test type boolean', () => {
   });
 
   test('Throws on invalid boolean value', async () => {
-    let res = await rq.post('/content-manager/collection-types/api::withboolean.withboolean', {
+    const res = await rq.post('/content-manager/collection-types/api::withboolean.withboolean', {
       body: { field: 'random' },
     });
 
diff --git a/packages/core/content-manager/server/tests/index.test.e2e.js b/packages/core/content-manager/server/tests/index.test.e2e.js
index d63d989e0b7..7bc113acbd6 100644
--- a/packages/core/content-manager/server/tests/index.test.e2e.js
+++ b/packages/core/content-manager/server/tests/index.test.e2e.js
@@ -69,7 +69,7 @@ describe('Content Manager End to End', () => {
     });
 
     test('Create tag1', async () => {
-      let { body } = await rq({
+      const { body } = await rq({
         url: '/content-manager/collection-types/api::tag.tag',
         method: 'POST',
         body: {
@@ -98,7 +98,7 @@ describe('Content Manager End to End', () => {
     });
 
     test('Create tag2', async () => {
-      let { body } = await rq({
+      const { body } = await rq({
         url: '/content-manager/collection-types/api::tag.tag',
         method: 'POST',
         body: {
@@ -127,7 +127,7 @@ describe('Content Manager End to End', () => {
     });
 
     test('Create tag3', async () => {
-      let { body } = await rq({
+      const { body } = await rq({
         url: '/content-manager/collection-types/api::tag.tag',
         method: 'POST',
         body: {
@@ -162,7 +162,7 @@ describe('Content Manager End to End', () => {
         date: '2019-08-13T00:00:00.000Z',
       };
 
-      let { body } = await rq({
+      const { body } = await rq({
         url: '/content-manager/collection-types/api::article.article',
         method: 'POST',
         body: entry,
@@ -197,7 +197,7 @@ describe('Content Manager End to End', () => {
         tags: [data.tags[0].id],
       };
 
-      let { body } = await rq({
+      const { body } = await rq({
         url: '/content-manager/collection-types/api::article.article',
         method: 'POST',
         body: entry,
@@ -227,13 +227,11 @@ describe('Content Manager End to End', () => {
     });
 
     test('Update article1 add tag2', async () => {
-      const entry = Object.assign({}, data.articles[0], {
-        tags: [data.tags[1].id],
-      });
+      const entry = { ...data.articles[0], tags: [data.tags[1].id] };
 
       cleanDate(entry);
 
-      let { body } = await rq({
+      const { body } = await rq({
         url: `/content-manager/collection-types/api::article.article/${entry.id}`,
         method: 'PUT',
         body: entry,
@@ -263,7 +261,7 @@ describe('Content Manager End to End', () => {
     });
 
     test('Update article1 add tag1 and tag3', async () => {
-      const entry = Object.assign({}, data.articles[0]);
+      const entry = { ...data.articles[0] };
       entry.tags = entry.tags.map(tag => tag.id);
 
       entry.tags.push(data.tags[0].id);
@@ -271,7 +269,7 @@ describe('Content Manager End to End', () => {
 
       cleanDate(entry);
 
-      let { body } = await rq({
+      const { body } = await rq({
         url: `/content-manager/collection-types/api::article.article/${entry.id}`,
         method: 'PUT',
         body: entry,
@@ -300,12 +298,12 @@ describe('Content Manager End to End', () => {
     });
 
     test('Update article1 remove one tag', async () => {
-      const entry = Object.assign({}, data.articles[0]);
+      const entry = { ...data.articles[0] };
       entry.tags = entry.tags.slice(1).map(tag => tag.id);
 
       cleanDate(entry);
 
-      let { body } = await rq({
+      const { body } = await rq({
         url: `/content-manager/collection-types/api::article.article/${entry.id}`,
         method: 'PUT',
         body: entry,
@@ -334,13 +332,11 @@ describe('Content Manager End to End', () => {
     });
 
     test('Update article1 remove all tag', async () => {
-      const entry = Object.assign({}, data.articles[0], {
-        tags: [],
-      });
+      const entry = { ...data.articles[0], tags: [] };
 
       cleanDate(entry);
 
-      let { body } = await rq({
+      const { body } = await rq({
         url: `/content-manager/collection-types/api::article.article/${entry.id}`,
         method: 'PUT',
         body: entry,
@@ -409,7 +405,7 @@ describe('Content Manager End to End', () => {
       expect(Array.isArray(articles[1].tags)).toBeTruthy();
       expect(articles[1].tags.length).toBe(1);
 
-      let { body: foundTag } = await rq({
+      const { body: foundTag } = await rq({
         url: `/content-manager/collection-types/api::tag.tag/${createdTag.id}`,
         method: 'GET',
       });
@@ -425,7 +421,7 @@ describe('Content Manager End to End', () => {
         },
       });
 
-      let { body: foundTag2 } = await rq({
+      const { body: foundTag2 } = await rq({
         url: `/content-manager/collection-types/api::tag.tag/${createdTag.id}`,
         method: 'GET',
       });
@@ -462,7 +458,7 @@ describe('Content Manager End to End', () => {
         tags: [createdTag.id],
       };
 
-      let { body } = await rq({
+      const { body } = await rq({
         url: '/content-manager/collection-types/api::articlewithtag.articlewithtag',
         method: 'POST',
         body: entry,
@@ -502,7 +498,7 @@ describe('Content Manager End to End', () => {
     });
 
     test('Create cat1', async () => {
-      let { body } = await rq({
+      const { body } = await rq({
         url: '/content-manager/collection-types/api::category.category',
         method: 'POST',
         body: {
@@ -531,7 +527,7 @@ describe('Content Manager End to End', () => {
     });
 
     test('Create cat2', async () => {
-      let { body } = await rq({
+      const { body } = await rq({
         url: '/content-manager/collection-types/api::category.category',
         method: 'POST',
         body: {
@@ -566,7 +562,7 @@ describe('Content Manager End to End', () => {
         category: data.categories[0].id,
       };
 
-      let { body } = await rq({
+      const { body } = await rq({
         url: '/content-manager/collection-types/api::article.article',
         method: 'POST',
         body: entry,
@@ -594,13 +590,11 @@ describe('Content Manager End to End', () => {
     });
 
     test('Update article1 with cat2', async () => {
-      const entry = Object.assign({}, data.articles[0], {
-        category: data.categories[1].id,
-      });
+      const entry = { ...data.articles[0], category: data.categories[1].id };
 
       cleanDate(entry);
 
-      let { body } = await rq({
+      const { body } = await rq({
         url: `/content-manager/collection-types/api::article.article/${entry.id}`,
         method: 'PUT',
         body: entry,
@@ -633,7 +627,7 @@ describe('Content Manager End to End', () => {
         content: 'Content 2',
       };
 
-      let { body } = await rq({
+      const { body } = await rq({
         url: '/content-manager/collection-types/api::article.article',
         method: 'POST',
         body: entry,
@@ -660,13 +654,11 @@ describe('Content Manager End to End', () => {
     });
 
     test('Update article2 with cat2', async () => {
-      const entry = Object.assign({}, data.articles[1], {
-        category: data.categories[1].id,
-      });
+      const entry = { ...data.articles[1], category: data.categories[1].id };
 
       cleanDate(entry);
 
-      let { body } = await rq({
+      const { body } = await rq({
         url: `/content-manager/collection-types/api::article.article/${entry.id}`,
         method: 'PUT',
         body: entry,
@@ -694,13 +686,13 @@ describe('Content Manager End to End', () => {
     });
 
     test('Update cat1 with article1', async () => {
-      const entry = Object.assign({}, data.categories[0]);
+      const entry = { ...data.categories[0] };
       entry.articles = entry.articles.map(article => article.id);
       entry.articles.push(data.articles[0].id);
 
       cleanDate(entry);
 
-      let { body } = await rq({
+      const { body } = await rq({
         url: `/content-manager/collection-types/api::category.category/${entry.id}`,
         method: 'PUT',
         body: entry,
@@ -732,7 +724,7 @@ describe('Content Manager End to End', () => {
         articles: [data.articles[0].id],
       };
 
-      let { body } = await rq({
+      const { body } = await rq({
         url: '/content-manager/collection-types/api::category.category',
         method: 'POST',
         body: entry,
@@ -759,7 +751,7 @@ describe('Content Manager End to End', () => {
     });
 
     test('Get article1 with cat3', async () => {
-      let { body } = await rq({
+      const { body } = await rq({
         url: `/content-manager/collection-types/api::article.article/${data.articles[0].id}`,
         method: 'GET',
       });
@@ -781,7 +773,7 @@ describe('Content Manager End to End', () => {
     });
 
     test('Get article2 with cat2', async () => {
-      let { body } = await rq({
+      const { body } = await rq({
         url: `/content-manager/collection-types/api::article.article/${data.articles[1].id}`,
         method: 'GET',
       });
@@ -803,7 +795,7 @@ describe('Content Manager End to End', () => {
     });
 
     test('Get cat1 without relations', async () => {
-      let { body } = await rq({
+      const { body } = await rq({
         url: `/content-manager/collection-types/api::category.category/${data.categories[0].id}`,
         method: 'GET',
       });
@@ -825,7 +817,7 @@ describe('Content Manager End to End', () => {
     });
 
     test('Get cat2 with article2', async () => {
-      let { body } = await rq({
+      const { body } = await rq({
         url: `/content-manager/collection-types/api::category.category/${data.categories[1].id}`,
         method: 'GET',
       });
@@ -848,7 +840,7 @@ describe('Content Manager End to End', () => {
     });
 
     test('Get cat3 with article1', async () => {
-      let { body } = await rq({
+      const { body } = await rq({
         url: `/content-manager/collection-types/api::category.category/${data.categories[2].id}`,
         method: 'GET',
       });
@@ -884,7 +876,7 @@ describe('Content Manager End to End', () => {
     });
 
     test('Create ref1', async () => {
-      let { body } = await rq({
+      const { body } = await rq({
         url: '/content-manager/collection-types/api::reference.reference',
         method: 'POST',
         body: {
@@ -916,7 +908,7 @@ describe('Content Manager End to End', () => {
         content: 'Content 1',
       };
 
-      let { body } = await rq({
+      const { body } = await rq({
         url: '/content-manager/collection-types/api::article.article',
         method: 'POST',
         body: entry,
@@ -943,13 +935,11 @@ describe('Content Manager End to End', () => {
     });
 
     test('Update article1 with ref1', async () => {
-      const entry = Object.assign({}, data.articles[0], {
-        reference: data.references[0].id,
-      });
+      const entry = { ...data.articles[0], reference: data.references[0].id };
 
       cleanDate(entry);
 
-      let { body } = await rq({
+      const { body } = await rq({
         url: `/content-manager/collection-types/api::article.article/${entry.id}`,
         method: 'PUT',
         body: entry,
@@ -982,7 +972,7 @@ describe('Content Manager End to End', () => {
         reference: data.references[0].id,
       };
 
-      let { body } = await rq({
+      const { body } = await rq({
         url: '/content-manager/collection-types/api::article.article',
         method: 'POST',
         body: entry,
diff --git a/packages/core/content-manager/server/tests/relation-list.test.e2e.js b/packages/core/content-manager/server/tests/relation-list.test.e2e.js
index ab685e5bb68..828797cc5fc 100644
--- a/packages/core/content-manager/server/tests/relation-list.test.e2e.js
+++ b/packages/core/content-manager/server/tests/relation-list.test.e2e.js
@@ -10,7 +10,7 @@ const { createAuthRequest } = require('../../../../../test/helpers/request');
 
 let strapi;
 let rq;
-let data = {
+const data = {
   products: [],
   shops: [],
 };
diff --git a/packages/core/content-manager/server/tests/search.test.e2e.js b/packages/core/content-manager/server/tests/search.test.e2e.js
index f430b29d080..bcdd063bb24 100644
--- a/packages/core/content-manager/server/tests/search.test.e2e.js
+++ b/packages/core/content-manager/server/tests/search.test.e2e.js
@@ -11,7 +11,7 @@ const CREATOR_FIELDS = ['updatedBy', 'createdBy'];
 const builder = createTestBuilder();
 let strapi;
 let rq;
-let data = {
+const data = {
   beds: [],
 };
 
diff --git a/packages/core/content-manager/server/tests/single-type.test.e2e.js b/packages/core/content-manager/server/tests/single-type.test.e2e.js
index f2e5279bfab..4c46957522a 100644
--- a/packages/core/content-manager/server/tests/single-type.test.e2e.js
+++ b/packages/core/content-manager/server/tests/single-type.test.e2e.js
@@ -8,7 +8,7 @@ const { createAuthRequest } = require('../../../../../test/helpers/request');
 const builder = createTestBuilder();
 let strapi;
 let rq;
-let uid = 'api::single-type-model.single-type-model';
+const uid = 'api::single-type-model.single-type-model';
 
 const ct = {
   kind: 'singleType',
diff --git a/packages/core/content-type-builder/server/controllers/validation/common.js b/packages/core/content-type-builder/server/controllers/validation/common.js
index bf25b0d1151..ff74fa514ab 100644
--- a/packages/core/content-type-builder/server/controllers/validation/common.js
+++ b/packages/core/content-type-builder/server/controllers/validation/common.js
@@ -24,31 +24,31 @@ const UID_REGEX = new RegExp('^[A-Za-z0-9-_.~]*$');
 
 const isValidName = {
   name: 'isValidName',
-  message: '${path} must match the following regex: ' + NAME_REGEX,
+  message: `\${path} must match the following regex: ${NAME_REGEX}`,
   test: val => val === '' || NAME_REGEX.test(val),
 };
 
 const isValidUID = {
   name: 'isValidUID',
-  message: '${path} must match the following regex: ' + UID_REGEX,
+  message: `\${path} must match the following regex: ${UID_REGEX}`,
   test: val => val === '' || UID_REGEX.test(val),
 };
 
 const isValidCategoryName = {
   name: 'isValidCategoryName',
-  message: '${path} must match the following regex: ' + CATEGORY_NAME_REGEX,
+  message: `\${path} must match the following regex: ${CATEGORY_NAME_REGEX}`,
   test: val => val === '' || CATEGORY_NAME_REGEX.test(val),
 };
 
 const isValidCollectionName = {
   name: 'isValidCollectionName',
-  message: '${path} must match the following regex: ' + COLLECTION_NAME_REGEX,
+  message: `\${path} must match the following regex: ${COLLECTION_NAME_REGEX}`,
   test: val => val === '' || COLLECTION_NAME_REGEX.test(val),
 };
 
 const isValidIcon = {
   name: 'isValidIcon',
-  message: '${path} must match the following regex: ' + ICON_REGEX,
+  message: `\${path} must match the following regex: ${ICON_REGEX}`,
   test: val => val === '' || ICON_REGEX.test(val),
 };
 
diff --git a/packages/core/content-type-builder/server/services/schema-builder/schema-handler.js b/packages/core/content-type-builder/server/services/schema-builder/schema-handler.js
index fba87f26df4..60cb4ede217 100644
--- a/packages/core/content-type-builder/server/services/schema-builder/schema-handler.js
+++ b/packages/core/content-type-builder/server/services/schema-builder/schema-handler.js
@@ -123,14 +123,14 @@ module.exports = function createSchemaHandler(infos) {
 
     setAttributes(newAttributes) {
       // delete old configurable attributes
-      for (let key in this.schema.attributes) {
+      for (const key in this.schema.attributes) {
         if (isConfigurable(this.schema.attributes[key])) {
           this.deleteAttribute(key);
         }
       }
 
       // set new Attributes
-      for (let key in newAttributes) {
+      for (const key in newAttributes) {
         this.setAttribute(key, newAttributes[key]);
       }
 
diff --git a/packages/core/content-type-builder/server/utils/attributes.js b/packages/core/content-type-builder/server/utils/attributes.js
index e90fc1fd1a4..6b0ed1e9a1a 100644
--- a/packages/core/content-type-builder/server/utils/attributes.js
+++ b/packages/core/content-type-builder/server/utils/attributes.js
@@ -45,8 +45,8 @@ const formatAttribute = (key, attribute) => {
   if (attribute.type === 'media') {
     return {
       type: 'media',
-      multiple: attribute.multiple ? true : false,
-      required: required ? true : false,
+      multiple: !!attribute.multiple,
+      required: !!required,
       configurable: configurable === false ? false : undefined,
       allowedTypes: attribute.allowedTypes,
       pluginOptions,
@@ -60,7 +60,7 @@ const formatAttribute = (key, attribute) => {
       target: attribute.target,
       targetAttribute: attribute.inversedBy || attribute.mappedBy || null,
       configurable: configurable === false ? false : undefined,
-      private: attribute.private ? true : false,
+      private: !!attribute.private,
       pluginOptions,
       // TODO: remove
       autoPopulate,
diff --git a/packages/core/content-type-builder/tests/collection-type.test.e2e.js b/packages/core/content-type-builder/tests/collection-type.test.e2e.js
index 91f732a7c95..9bf2a8bc38e 100644
--- a/packages/core/content-type-builder/tests/collection-type.test.e2e.js
+++ b/packages/core/content-type-builder/tests/collection-type.test.e2e.js
@@ -1,6 +1,7 @@
 /**
  * Integration test for the content-type-builder content types management apis
  */
+
 'use strict';
 
 const { createStrapiInstance } = require('../../../../test/helpers/strapi');
diff --git a/packages/core/content-type-builder/tests/single-type.test.e2e.js b/packages/core/content-type-builder/tests/single-type.test.e2e.js
index a86d6c1fdf7..b6c9263bb8b 100644
--- a/packages/core/content-type-builder/tests/single-type.test.e2e.js
+++ b/packages/core/content-type-builder/tests/single-type.test.e2e.js
@@ -1,6 +1,7 @@
 /**
  * Integration test for the content-type-builder content types management apis
  */
+
 'use strict';
 
 const { createStrapiInstance } = require('../../../../test/helpers/strapi');
diff --git a/packages/core/database/lib/__tests__/lifecycles.test.js b/packages/core/database/lib/__tests__/lifecycles.test.js
index 717942bcec4..1dbbf352558 100644
--- a/packages/core/database/lib/__tests__/lifecycles.test.js
+++ b/packages/core/database/lib/__tests__/lifecycles.test.js
@@ -6,7 +6,7 @@ describe('LifecycleProvider', () => {
   describe('run', () => {
     /** @type {import("../lifecycles").LifecycleProvider} */
     let provider;
-    let dbMetadataGetStub = jest.fn(uid => ({ uid, name: 'TestModel' }));
+    const dbMetadataGetStub = jest.fn(uid => ({ uid, name: 'TestModel' }));
 
     beforeEach(() => {
       const db = {
diff --git a/packages/core/database/lib/connection.js b/packages/core/database/lib/connection.js
index e03e884cb2c..67201993cb6 100644
--- a/packages/core/database/lib/connection.js
+++ b/packages/core/database/lib/connection.js
@@ -1,5 +1,6 @@
 /* eslint-disable node/no-missing-require */
 /* eslint-disable node/no-extraneous-require */
+
 'use strict';
 
 const knex = require('knex');
diff --git a/packages/core/database/lib/dialects/dialect.js b/packages/core/database/lib/dialects/dialect.js
index f3b374f78c8..5e92b31a7fd 100644
--- a/packages/core/database/lib/dialects/dialect.js
+++ b/packages/core/database/lib/dialects/dialect.js
@@ -6,6 +6,7 @@ class Dialect {
   }
 
   configure() {}
+
   initialize() {}
 
   getSqlType(type) {
@@ -29,6 +30,7 @@ class Dialect {
   }
 
   async startSchemaUpdate() {}
+
   async endSchemaUpdate() {}
 
   transformErrors(error) {
diff --git a/packages/core/database/lib/dialects/mysql/index.js b/packages/core/database/lib/dialects/mysql/index.js
index dcace979d58..9e01d5e0b1d 100644
--- a/packages/core/database/lib/dialects/mysql/index.js
+++ b/packages/core/database/lib/dialects/mysql/index.js
@@ -15,12 +15,12 @@ class MysqlDialect extends Dialect {
     this.db.config.connection.connection.bigNumberStrings = true;
     this.db.config.connection.connection.typeCast = (field, next) => {
       if (field.type === 'DECIMAL' || field.type === 'NEWDECIMAL') {
-        var value = field.string();
+        const value = field.string();
         return value === null ? null : Number(value);
       }
 
       if (field.type === 'TINY' && field.length === 1) {
-        let value = field.string();
+        const value = field.string();
         return value ? value === '1' : null;
       }
 
diff --git a/packages/core/database/lib/entity-manager.js b/packages/core/database/lib/entity-manager.js
index 0233bb1e235..7bb18e50325 100644
--- a/packages/core/database/lib/entity-manager.js
+++ b/packages/core/database/lib/entity-manager.js
@@ -817,7 +817,7 @@ const createEntityManager = db => {
         populate,
       });
 
-      return Object.assign({}, entity, entry);
+      return { ...entity, ...entry };
     },
 
     // TODO: support multiple relations at once with the populate syntax
diff --git a/packages/core/database/lib/fields.js b/packages/core/database/lib/fields.js
index ebf08b29482..103f411f6ba 100644
--- a/packages/core/database/lib/fields.js
+++ b/packages/core/database/lib/fields.js
@@ -63,11 +63,11 @@ class BooleanField extends Field {
 
     if (strVal === '1') {
       return true;
-    } else if (strVal === '0') {
+    }
+    if (strVal === '0') {
       return false;
-    } else {
-      return null;
     }
+    return null;
   }
 }
 
@@ -131,7 +131,7 @@ const parseDate = value => {
     );
   }
 
-  let date = dateFns.parseISO(extractedValue);
+  const date = dateFns.parseISO(extractedValue);
   if (!dateFns.isValid(date)) {
     throw new InvalidDateError(`Invalid date`);
   }
diff --git a/packages/core/database/lib/metadata/relations.js b/packages/core/database/lib/metadata/relations.js
index 155453b456d..178906cd4c8 100644
--- a/packages/core/database/lib/metadata/relations.js
+++ b/packages/core/database/lib/metadata/relations.js
@@ -75,12 +75,8 @@ const createOneToMany = (attributeName, attribute, meta, metadata) => {
       attributeName,
       meta,
     });
-  } else {
-    if (isOwner(attribute)) {
-      throw new Error(
-        'one side of a oneToMany cannot be the owner side in a bidirectional relation'
-      );
-    }
+  } else if (isOwner(attribute)) {
+    throw new Error('one side of a oneToMany cannot be the owner side in a bidirectional relation');
   }
 };
 
@@ -169,7 +165,7 @@ const createManyToMany = (attributeName, attribute, meta, metadata) => {
  * @param {ModelMetadata} meta
  * @param {Metadata} metadata
  */
-const createMorphToOne = (attributeName, attribute /*meta, metadata*/) => {
+const createMorphToOne = (attributeName, attribute /* meta, metadata */) => {
   const idColumnName = 'target_id';
   const typeColumnName = 'target_type';
 
@@ -354,7 +350,7 @@ const createRelation = (attributeName, attribute, meta, metadata) => {
  * @param {string} param.attributeName name of the associated attribute
  * @param {Object} param.meta model metadata
  */
-const createJoinColum = (metadata, { attribute, attributeName /*meta */ }) => {
+const createJoinColum = (metadata, { attribute, attributeName /* meta */ }) => {
   const targetMeta = metadata.get(attribute.target);
 
   const joinColumnName = _.snakeCase(`${attributeName}_id`);
@@ -395,7 +391,7 @@ const createJoinTable = (metadata, { attributeName, attribute, meta }) => {
 
   const joinTableName = _.snakeCase(`${meta.tableName}_${attributeName}_links`);
 
-  let joinColumnName = _.snakeCase(`${meta.singularName}_id`);
+  const joinColumnName = _.snakeCase(`${meta.singularName}_id`);
   let inverseJoinColumnName = _.snakeCase(`${targetMeta.singularName}_id`);
 
   // if relation is slef referencing
diff --git a/packages/core/database/lib/query/helpers/join.js b/packages/core/database/lib/query/helpers/join.js
index c46cd5133eb..3539cf15c41 100644
--- a/packages/core/database/lib/query/helpers/join.js
+++ b/packages/core/database/lib/query/helpers/join.js
@@ -32,7 +32,7 @@ const createJoin = (ctx, { alias, attributeName, attribute }) => {
 
   const tragetMeta = db.metadata.get(attribute.target);
 
-  const joinColumn = attribute.joinColumn;
+  const { joinColumn } = attribute;
 
   if (joinColumn) {
     const subAlias = qb.getAlias();
@@ -46,7 +46,7 @@ const createJoin = (ctx, { alias, attributeName, attribute }) => {
     return subAlias;
   }
 
-  const joinTable = attribute.joinTable;
+  const { joinTable } = attribute;
   if (joinTable) {
     return createPivotJoin(qb, joinTable, alias, tragetMeta);
   }
diff --git a/packages/core/database/lib/schema/diff.js b/packages/core/database/lib/schema/diff.js
index abd98bb85e8..318c5c1ad98 100644
--- a/packages/core/database/lib/schema/diff.js
+++ b/packages/core/database/lib/schema/diff.js
@@ -117,7 +117,7 @@ module.exports = db => {
 
   const diffDefault = (oldColumn, column) => {
     const oldDefaultTo = oldColumn.defaultTo;
-    const defaultTo = column.defaultTo;
+    const { defaultTo } = column;
 
     if (oldDefaultTo === null || _.toLower(oldDefaultTo) === 'null') {
       return _.isNil(defaultTo) || _.toLower(defaultTo) === 'null';
diff --git a/packages/core/database/lib/schema/index.js b/packages/core/database/lib/schema/index.js
index b8f97a3d0a3..2a395d65e3e 100644
--- a/packages/core/database/lib/schema/index.js
+++ b/packages/core/database/lib/schema/index.js
@@ -87,7 +87,6 @@ const createSchemaProvider = db => {
       }
 
       debug('Schema unchanged');
-      return;
     },
   };
 };
diff --git a/packages/core/email/server/controllers/email.js b/packages/core/email/server/controllers/email.js
index 12b60d2a06a..8ae0e5c5877 100644
--- a/packages/core/email/server/controllers/email.js
+++ b/packages/core/email/server/controllers/email.js
@@ -10,7 +10,7 @@ const { ApplicationError } = require('@strapi/utils').errors;
  */
 module.exports = {
   async send(ctx) {
-    let options = ctx.request.body;
+    const options = ctx.request.body;
 
     try {
       await strapi
diff --git a/packages/core/strapi/bin/strapi.js b/packages/core/strapi/bin/strapi.js
index b2b63fe6388..74a0617066c 100755
--- a/packages/core/strapi/bin/strapi.js
+++ b/packages/core/strapi/bin/strapi.js
@@ -1,4 +1,5 @@
 #!/usr/bin/env node
+
 'use strict';
 
 // FIXME
@@ -13,7 +14,7 @@ const program = new Command();
 const packageJSON = require('../package.json');
 
 const checkCwdIsStrapiApp = name => {
-  let logErrorAndExit = () => {
+  const logErrorAndExit = () => {
     console.log(
       `You need to run ${yellow(
         `strapi ${name}`
@@ -23,7 +24,7 @@ const checkCwdIsStrapiApp = name => {
   };
 
   try {
-    const pkgJSON = require(process.cwd() + '/package.json');
+    const pkgJSON = require(`${process.cwd()}/package.json`);
     if (!_.has(pkgJSON, 'dependencies.@strapi/strapi')) {
       logErrorAndExit(name);
     }
@@ -69,7 +70,7 @@ program
   .command('version')
   .description('Output the version of Strapi')
   .action(() => {
-    process.stdout.write(packageJSON.version + '\n');
+    process.stdout.write(`${packageJSON.version}\n`);
     process.exit(0);
   });
 
diff --git a/packages/core/strapi/lib/commands/__tests__/generate-template.test.js b/packages/core/strapi/lib/commands/__tests__/generate-template.test.js
index 8ff4d606276..de6bfbeba5f 100644
--- a/packages/core/strapi/lib/commands/__tests__/generate-template.test.js
+++ b/packages/core/strapi/lib/commands/__tests__/generate-template.test.js
@@ -1,4 +1,5 @@
 'use strict';
+
 jest.mock('fs-extra', () => ({
   ensureDir: jest.fn(() => Promise.resolve()),
   copy: jest.fn(() => Promise.resolve()),
diff --git a/packages/core/strapi/lib/commands/build.js b/packages/core/strapi/lib/commands/build.js
index c96f9947ae3..29b99dfd8db 100644
--- a/packages/core/strapi/lib/commands/build.js
+++ b/packages/core/strapi/lib/commands/build.js
@@ -1,6 +1,6 @@
 'use strict';
 
-const strapi = require('../');
+const strapi = require('..');
 const { buildAdmin } = require('./builders');
 
 /**
diff --git a/packages/core/strapi/lib/commands/develop.js b/packages/core/strapi/lib/commands/develop.js
index 23f25b7c813..4d1df431abe 100644
--- a/packages/core/strapi/lib/commands/develop.js
+++ b/packages/core/strapi/lib/commands/develop.js
@@ -97,7 +97,6 @@ const primaryProcess = async ({ distDir, appDir, build, isTSProject, watchAdmin,
       case 'stop':
         process.exit(1);
       default:
-        return;
     }
   });
 
@@ -108,7 +107,7 @@ const workerProcess = ({ appDir, distDir, watchAdmin, polling, isTSProject }) =>
   const strapiInstance = strapi({
     distDir,
     autoReload: true,
-    serveAdminPanel: watchAdmin ? false : true,
+    serveAdminPanel: !watchAdmin,
   });
 
   const adminWatchIgnoreFiles = strapiInstance.config.get('admin.watchIgnoreFiles', []);
diff --git a/packages/core/strapi/lib/commands/install.js b/packages/core/strapi/lib/commands/install.js
index a5434182e0c..288a8352222 100644
--- a/packages/core/strapi/lib/commands/install.js
+++ b/packages/core/strapi/lib/commands/install.js
@@ -28,8 +28,8 @@ module.exports = async plugins => {
 
     // check if rebuild is necessary
     let shouldRebuild = false;
-    for (let name of plugins) {
-      let pkgPath = findPackagePath(`@strapi/plugin-${name}`);
+    for (const name of plugins) {
+      const pkgPath = findPackagePath(`@strapi/plugin-${name}`);
       if (existsSync(join(pkgPath, 'admin', 'src', 'index.js'))) {
         shouldRebuild = true;
       }
diff --git a/packages/core/strapi/lib/commands/opt-in-telemetry.js b/packages/core/strapi/lib/commands/opt-in-telemetry.js
index 9086d0fbe1b..f811278755f 100644
--- a/packages/core/strapi/lib/commands/opt-in-telemetry.js
+++ b/packages/core/strapi/lib/commands/opt-in-telemetry.js
@@ -40,16 +40,15 @@ const generateNewPackageJSON = packageObj => {
         telemetryDisabled: false,
       },
     };
-  } else {
-    return {
-      ...packageObj,
-      strapi: {
-        ...packageObj.strapi,
-        uuid: packageObj.strapi.uuid ? packageObj.strapi.uuid : uuidv4(),
-        telemetryDisabled: false,
-      },
-    };
   }
+  return {
+    ...packageObj,
+    strapi: {
+      ...packageObj.strapi,
+      uuid: packageObj.strapi.uuid ? packageObj.strapi.uuid : uuidv4(),
+      telemetryDisabled: false,
+    },
+  };
 };
 
 const sendEvent = async uuid => {
@@ -64,7 +63,7 @@ const sendEvent = async uuid => {
       headers: { 'Content-Type': 'application/json' },
     });
   } catch (e) {
-    //...
+    // ...
   }
 };
 
diff --git a/packages/core/strapi/lib/commands/opt-out-telemetry.js b/packages/core/strapi/lib/commands/opt-out-telemetry.js
index 6fa60ea4545..2dafd8a0f0c 100644
--- a/packages/core/strapi/lib/commands/opt-out-telemetry.js
+++ b/packages/core/strapi/lib/commands/opt-out-telemetry.js
@@ -38,7 +38,7 @@ const sendEvent = async uuid => {
       headers: { 'Content-Type': 'application/json' },
     });
   } catch (e) {
-    //...
+    // ...
   }
 };
 
diff --git a/packages/core/strapi/lib/commands/start.js b/packages/core/strapi/lib/commands/start.js
index 9f0299e6315..829a7cf66e0 100644
--- a/packages/core/strapi/lib/commands/start.js
+++ b/packages/core/strapi/lib/commands/start.js
@@ -1,4 +1,5 @@
 'use strict';
+
 const fs = require('fs');
 const tsUtils = require('@strapi/typescript-utils');
 const strapi = require('../index');
diff --git a/packages/core/strapi/lib/commands/uninstall.js b/packages/core/strapi/lib/commands/uninstall.js
index 31d091d1c4f..d00e6074034 100644
--- a/packages/core/strapi/lib/commands/uninstall.js
+++ b/packages/core/strapi/lib/commands/uninstall.js
@@ -26,8 +26,8 @@ module.exports = async (plugins, { deleteFiles }) => {
   try {
     // verify should rebuild before removing the pacakge
     let shouldRebuild = false;
-    for (let name of plugins) {
-      let pkgPath = findPackagePath(`@strapi/plugin-${name}`);
+    for (const name of plugins) {
+      const pkgPath = findPackagePath(`@strapi/plugin-${name}`);
       if (existsSync(join(pkgPath, 'admin', 'src', 'index.js'))) {
         shouldRebuild = true;
       }
@@ -46,7 +46,7 @@ module.exports = async (plugins, { deleteFiles }) => {
 
     if (deleteFiles === true || answers.deleteFiles === true) {
       loader.start('Deleting old files');
-      for (let name of plugins) {
+      for (const name of plugins) {
         const pluginDir = join(dir, 'extensions', name);
         if (existsSync(pluginDir)) {
           removeSync(pluginDir);
diff --git a/packages/core/strapi/lib/core-api/__tests__/controller.test.js b/packages/core/strapi/lib/core-api/__tests__/controller.test.js
index 60cdf9e2514..93f589b0e3f 100644
--- a/packages/core/strapi/lib/core-api/__tests__/controller.test.js
+++ b/packages/core/strapi/lib/core-api/__tests__/controller.test.js
@@ -1,4 +1,5 @@
 'use strict';
+
 const { createController } = require('../controller');
 
 describe('Default Controller', () => {
diff --git a/packages/core/strapi/lib/core/domain/content-type/index.js b/packages/core/strapi/lib/core/domain/content-type/index.js
index 99a9d725e82..6d390ba2289 100644
--- a/packages/core/strapi/lib/core/domain/content-type/index.js
+++ b/packages/core/strapi/lib/core/domain/content-type/index.js
@@ -114,7 +114,7 @@ const createContentType = (uid, definition) => {
 };
 
 const getGlobalId = (model, modelName, prefix) => {
-  let globalId = prefix ? `${prefix}-${modelName}` : modelName;
+  const globalId = prefix ? `${prefix}-${modelName}` : modelName;
 
   return model.globalId || _.upperFirst(_.camelCase(globalId));
 };
diff --git a/packages/core/strapi/lib/core/domain/module/validation.js b/packages/core/strapi/lib/core/domain/module/validation.js
index 1c20d9b5e98..6ffa18d4d9d 100644
--- a/packages/core/strapi/lib/core/domain/module/validation.js
+++ b/packages/core/strapi/lib/core/domain/module/validation.js
@@ -12,9 +12,8 @@ const strapiServerSchema = yup
     routes: yup.lazy(value => {
       if (Array.isArray(value)) {
         return yup.array();
-      } else {
-        return yup.object();
       }
+      return yup.object();
     }),
     controllers: yup.object(),
     services: yup.object(),
diff --git a/packages/core/strapi/lib/core/loaders/plugins/get-enabled-plugins.js b/packages/core/strapi/lib/core/loaders/plugins/get-enabled-plugins.js
index bae4f51eedc..3763af0671d 100644
--- a/packages/core/strapi/lib/core/loaders/plugins/get-enabled-plugins.js
+++ b/packages/core/strapi/lib/core/loaders/plugins/get-enabled-plugins.js
@@ -26,7 +26,7 @@ const toDetailedDeclaration = declaration => {
     return { enabled: declaration };
   }
 
-  let detailedDeclaration = pick(['enabled'], declaration);
+  const detailedDeclaration = pick(['enabled'], declaration);
   if (has('resolve', declaration)) {
     let pathToPlugin = '';
 
diff --git a/packages/core/strapi/lib/core/loaders/plugins/index.js b/packages/core/strapi/lib/core/loaders/plugins/index.js
index 817d13975d9..0c51d5823b8 100644
--- a/packages/core/strapi/lib/core/loaders/plugins/index.js
+++ b/packages/core/strapi/lib/core/loaders/plugins/index.js
@@ -40,11 +40,10 @@ const applyUserExtension = async plugins => {
     for (const ctName in plugin.contentTypes) {
       const extendedSchema = get([pluginName, 'content-types', ctName, 'schema'], extendedSchemas);
       if (extendedSchema) {
-        plugin.contentTypes[ctName].schema = Object.assign(
-          {},
-          plugin.contentTypes[ctName].schema,
-          extendedSchema
-        );
+        plugin.contentTypes[ctName].schema = {
+          ...plugin.contentTypes[ctName].schema,
+          ...extendedSchema,
+        };
       }
     }
     // second: execute strapi-server extension
diff --git a/packages/core/strapi/lib/core/registries/config.js b/packages/core/strapi/lib/core/registries/config.js
index c58cf329678..87c36169a85 100644
--- a/packages/core/strapi/lib/core/registries/config.js
+++ b/packages/core/strapi/lib/core/registries/config.js
@@ -3,7 +3,7 @@
 const _ = require('lodash');
 
 module.exports = (initialConfig = {}) => {
-  const _config = Object.assign({}, initialConfig); // not deep clone because it would break some config
+  const _config = { ...initialConfig }; // not deep clone because it would break some config
 
   return {
     ..._config, // TODO: to remove
diff --git a/packages/core/strapi/lib/core/utils.js b/packages/core/strapi/lib/core/utils.js
index bcb214c3139..f4cbb6e94d6 100644
--- a/packages/core/strapi/lib/core/utils.js
+++ b/packages/core/strapi/lib/core/utils.js
@@ -7,25 +7,22 @@ const hasNamespace = (name, namespace) => {
 
   if (namespace.endsWith('::')) {
     return name.startsWith(namespace);
-  } else {
-    return name.startsWith(`${namespace}.`);
   }
+  return name.startsWith(`${namespace}.`);
 };
 
 const addNamespace = (name, namespace) => {
   if (namespace.endsWith('::')) {
     return `${namespace}${name}`;
-  } else {
-    return `${namespace}.${name}`;
   }
+  return `${namespace}.${name}`;
 };
 
 const removeNamespace = (name, namespace) => {
   if (namespace.endsWith('::')) {
     return name.replace(namespace, '');
-  } else {
-    return name.replace(`${namespace}.`, '');
   }
+  return name.replace(`${namespace}.`, '');
 };
 
 module.exports = {
diff --git a/packages/core/strapi/lib/factories.js b/packages/core/strapi/lib/factories.js
index cb90ae021da..122ab9362d4 100644
--- a/packages/core/strapi/lib/factories.js
+++ b/packages/core/strapi/lib/factories.js
@@ -12,7 +12,7 @@ const createCoreController = (uid, cfg = {}) => {
       contentType: strapi.contentType(uid),
     });
 
-    let userCtrl = typeof cfg === 'function' ? cfg({ strapi }) : cfg;
+    const userCtrl = typeof cfg === 'function' ? cfg({ strapi }) : cfg;
 
     for (const methodName of Object.keys(baseController)) {
       if (userCtrl[methodName] === undefined) {
@@ -31,7 +31,7 @@ const createCoreService = (uid, cfg = {}) => {
       contentType: strapi.contentType(uid),
     });
 
-    let userService = typeof cfg === 'function' ? cfg({ strapi }) : cfg;
+    const userService = typeof cfg === 'function' ? cfg({ strapi }) : cfg;
 
     for (const methodName of Object.keys(baseService)) {
       if (userService[methodName] === undefined) {
diff --git a/packages/core/strapi/lib/load/filepath-to-prop-path.js b/packages/core/strapi/lib/load/filepath-to-prop-path.js
index 096abb56a08..afd48f1a902 100644
--- a/packages/core/strapi/lib/load/filepath-to-prop-path.js
+++ b/packages/core/strapi/lib/load/filepath-to-prop-path.js
@@ -8,7 +8,7 @@ const _ = require('lodash');
  * @param {boolean} useFileNameAsKey - wethear to skip the last path key
  */
 module.exports = (filePath, useFileNameAsKey = true) => {
-  let cleanPath = filePath.startsWith('./') ? filePath.slice(2) : filePath;
+  const cleanPath = filePath.startsWith('./') ? filePath.slice(2) : filePath;
 
   const prop = cleanPath
     .replace(/(\.settings|\.json|\.js)/g, '')
diff --git a/packages/core/strapi/lib/load/load-files.js b/packages/core/strapi/lib/load/load-files.js
index e7c35ed4602..ccb4f9a178a 100644
--- a/packages/core/strapi/lib/load/load-files.js
+++ b/packages/core/strapi/lib/load/load-files.js
@@ -26,7 +26,7 @@ const loadFiles = async (
   const root = {};
   const files = await glob(pattern, { cwd: dir, ...globArgs });
 
-  for (let file of files) {
+  for (const file of files) {
     const absolutePath = path.resolve(dir, file);
 
     // load module
diff --git a/packages/core/strapi/lib/middlewares/logger.js b/packages/core/strapi/lib/middlewares/logger.js
index a613057453a..88bb7ef7117 100644
--- a/packages/core/strapi/lib/middlewares/logger.js
+++ b/packages/core/strapi/lib/middlewares/logger.js
@@ -1,4 +1,5 @@
 'use strict';
+
 const chalk = require('chalk');
 
 const codeToColor = code => {
diff --git a/packages/core/strapi/lib/middlewares/response-time.js b/packages/core/strapi/lib/middlewares/response-time.js
index c8510b4017d..a3f5e544da3 100644
--- a/packages/core/strapi/lib/middlewares/response-time.js
+++ b/packages/core/strapi/lib/middlewares/response-time.js
@@ -10,6 +10,6 @@ module.exports = () => {
     await next();
 
     const delta = Math.ceil(Date.now() - start);
-    ctx.set('X-Response-Time', delta + 'ms');
+    ctx.set('X-Response-Time', `${delta}ms`);
   };
 };
diff --git a/packages/core/strapi/lib/middlewares/responses.js b/packages/core/strapi/lib/middlewares/responses.js
index b66e3895df5..370152a80ea 100644
--- a/packages/core/strapi/lib/middlewares/responses.js
+++ b/packages/core/strapi/lib/middlewares/responses.js
@@ -9,7 +9,7 @@ module.exports = (config = {}) => {
   return async (ctx, next) => {
     await next();
 
-    const status = ctx.status;
+    const { status } = ctx;
     const handler = prop(`handlers.${status}`, config);
 
     if (isFunction(handler)) {
diff --git a/packages/core/strapi/lib/middlewares/session.js b/packages/core/strapi/lib/middlewares/session.js
index b60312f58e4..87f185246c1 100644
--- a/packages/core/strapi/lib/middlewares/session.js
+++ b/packages/core/strapi/lib/middlewares/session.js
@@ -12,12 +12,12 @@ const defaultConfig = {
   signed: true,
   rolling: false,
   renew: false,
-  secure: process.env.NODE_ENV === 'production' ? true : false,
+  secure: process.env.NODE_ENV === 'production',
   sameSite: null,
 };
 
 module.exports = (userConfig, { strapi }) => {
-  const keys = strapi.server.app.keys;
+  const { keys } = strapi.server.app;
   if (!isArray(keys) || isEmpty(keys) || keys.some(isEmpty)) {
     throw new Error(
       `App keys are required. Please set app.keys in config/server.js (ex: keys: ['myKeyA', 'myKeyB'])`
diff --git a/packages/core/strapi/lib/services/auth/index.js b/packages/core/strapi/lib/services/auth/index.js
index ccf96614af6..e40442f5b43 100644
--- a/packages/core/strapi/lib/services/auth/index.js
+++ b/packages/core/strapi/lib/services/auth/index.js
@@ -78,8 +78,6 @@ const createAuthentication = () => {
       if (typeof auth.strategy.verify === 'function') {
         return auth.strategy.verify(auth, config);
       }
-
-      return;
     },
   };
 };
diff --git a/packages/core/strapi/lib/services/entity-service/__tests__/entity-service.test.js b/packages/core/strapi/lib/services/entity-service/__tests__/entity-service.test.js
index 5ad4924b55e..2d0a4c4f6ab 100644
--- a/packages/core/strapi/lib/services/entity-service/__tests__/entity-service.test.js
+++ b/packages/core/strapi/lib/services/entity-service/__tests__/entity-service.test.js
@@ -3,7 +3,7 @@
 jest.mock('bcryptjs', () => ({ hashSync: () => 'secret-password' }));
 
 const { EventEmitter } = require('events');
-const createEntityService = require('../');
+const createEntityService = require('..');
 const entityValidator = require('../../entity-validator');
 
 describe('Entity service', () => {
diff --git a/packages/core/strapi/lib/services/entity-service/components.js b/packages/core/strapi/lib/services/entity-service/components.js
index e93a7d360d5..c9938e8a6c7 100644
--- a/packages/core/strapi/lib/services/entity-service/components.js
+++ b/packages/core/strapi/lib/services/entity-service/components.js
@@ -307,9 +307,9 @@ const deleteComponents = async (uid, entityToDelete) => {
   }
 };
 
-/***************************
+/** *************************
     Component queries
-***************************/
+************************** */
 
 // components can have nested compos so this must be recursive
 const createComponent = async (uid, data) => {
diff --git a/packages/core/strapi/lib/services/entity-service/index.js b/packages/core/strapi/lib/services/entity-service/index.js
index 9dcc4b5f943..e11fe997618 100644
--- a/packages/core/strapi/lib/services/entity-service/index.js
+++ b/packages/core/strapi/lib/services/entity-service/index.js
@@ -47,7 +47,7 @@ module.exports = ctx => {
         throw new Error(`Decorator must be a function, received ${typeof decorator}`);
       }
 
-      this.implementation = Object.assign({}, this.implementation, decorator(this.implementation));
+      this.implementation = { ...this.implementation, ...decorator(this.implementation) };
       return this;
     },
   };
diff --git a/packages/core/strapi/lib/services/entity-validator/index.js b/packages/core/strapi/lib/services/entity-validator/index.js
index 448d19da039..15a35cfe278 100644
--- a/packages/core/strapi/lib/services/entity-validator/index.js
+++ b/packages/core/strapi/lib/services/entity-validator/index.js
@@ -2,6 +2,7 @@
  * Entity validator
  * Module that will validate input data for entity creation or edition
  */
+
 'use strict';
 
 const { has, assoc, prop, isObject } = require('lodash/fp');
diff --git a/packages/core/strapi/lib/services/entity-validator/validators.js b/packages/core/strapi/lib/services/entity-validator/validators.js
index bfcad9ed87a..def75c6c31b 100644
--- a/packages/core/strapi/lib/services/entity-validator/validators.js
+++ b/packages/core/strapi/lib/services/entity-validator/validators.js
@@ -143,7 +143,7 @@ const addUniqueValidator = (validator, { attr, model, updatedAttribute, entity }
       return true;
     }
 
-    let whereParams = entity
+    const whereParams = entity
       ? { $and: [{ [updatedAttribute.name]: value }, { $not: { id: entity.id } }] }
       : { [updatedAttribute.name]: value };
 
diff --git a/packages/core/strapi/lib/services/event-hub.js b/packages/core/strapi/lib/services/event-hub.js
index 79800a2bee9..175ef992c9a 100644
--- a/packages/core/strapi/lib/services/event-hub.js
+++ b/packages/core/strapi/lib/services/event-hub.js
@@ -1,6 +1,7 @@
 /**
  * The event hub is Strapi's event control center.
  */
+
 'use strict';
 
 const EventEmitter = require('events');
diff --git a/packages/core/strapi/lib/services/metrics/index.js b/packages/core/strapi/lib/services/metrics/index.js
index accd4068a63..5bd85a36040 100644
--- a/packages/core/strapi/lib/services/metrics/index.js
+++ b/packages/core/strapi/lib/services/metrics/index.js
@@ -1,4 +1,5 @@
 'use strict';
+
 /**
  * Strapi telemetry package.
  * You can learn more at https://docs.strapi.io/developer-docs/latest/getting-started/usage-information.html
diff --git a/packages/core/strapi/lib/services/server/koa.js b/packages/core/strapi/lib/services/server/koa.js
index 1c98f6160f3..0791efe3c80 100644
--- a/packages/core/strapi/lib/services/server/koa.js
+++ b/packages/core/strapi/lib/services/server/koa.js
@@ -4,7 +4,7 @@ const { isNil, camelCase } = require('lodash/fp');
 const Koa = require('koa');
 const createError = require('http-errors');
 const delegate = require('delegates');
-var statuses = require('statuses');
+const statuses = require('statuses');
 const { formatHttpError } = require('../errors');
 
 const addCustomMethods = app => {
diff --git a/packages/core/strapi/lib/services/server/register-middlewares.js b/packages/core/strapi/lib/services/server/register-middlewares.js
index de330f29d7a..69f7aaaae24 100644
--- a/packages/core/strapi/lib/services/server/register-middlewares.js
+++ b/packages/core/strapi/lib/services/server/register-middlewares.js
@@ -104,8 +104,6 @@ const checkRequiredMiddlewares = middlewares => {
       )}".`
     );
   }
-
-  return;
 };
 
 module.exports = registerApplicationMiddlewares;
diff --git a/packages/core/strapi/lib/services/utils/upload-files.js b/packages/core/strapi/lib/services/utils/upload-files.js
index f12fdf56ea2..dcbc1bf8b10 100644
--- a/packages/core/strapi/lib/services/utils/upload-files.js
+++ b/packages/core/strapi/lib/services/utils/upload-files.js
@@ -23,7 +23,7 @@ module.exports = async (uid, entity, files) => {
       return uid;
     }
 
-    let currentPath = [];
+    const currentPath = [];
     let tmpModel = modelDef;
     let modelUID = uid;
 
diff --git a/packages/core/strapi/lib/services/webhook-runner.js b/packages/core/strapi/lib/services/webhook-runner.js
index 532b9832831..3bf37778621 100644
--- a/packages/core/strapi/lib/services/webhook-runner.js
+++ b/packages/core/strapi/lib/services/webhook-runner.js
@@ -1,6 +1,7 @@
 /**
  * The event hub is Strapi's event control center.
  */
+
 'use strict';
 
 const debug = require('debug')('strapi:webhook');
diff --git a/packages/core/strapi/lib/services/webhook-store.js b/packages/core/strapi/lib/services/webhook-store.js
index 9aa87eca975..39423edbc70 100644
--- a/packages/core/strapi/lib/services/webhook-store.js
+++ b/packages/core/strapi/lib/services/webhook-store.js
@@ -1,6 +1,7 @@
 /**
  * Webhook store is the implementation of webhook storage over the core_store
  */
+
 'use strict';
 
 const webhookModel = {
diff --git a/packages/core/strapi/lib/services/worker-queue.js b/packages/core/strapi/lib/services/worker-queue.js
index 7eaabfc174f..bece4f70b82 100644
--- a/packages/core/strapi/lib/services/worker-queue.js
+++ b/packages/core/strapi/lib/services/worker-queue.js
@@ -1,6 +1,7 @@
 /**
  * Simple worker queue in memory
  */
+
 'use strict';
 
 const debug = require('debug')('strapi:worker-queue');
diff --git a/packages/core/strapi/lib/utils/addSlash.js b/packages/core/strapi/lib/utils/addSlash.js
index d30bf5bebc3..81dd403c337 100644
--- a/packages/core/strapi/lib/utils/addSlash.js
+++ b/packages/core/strapi/lib/utils/addSlash.js
@@ -4,7 +4,7 @@ module.exports = path => {
   if (typeof path !== 'string') throw new Error('admin.url must be a string');
   if (path === '' || path === '/') return '/';
 
-  if (path[0] != '/') path = '/' + path;
-  if (path[path.length - 1] != '/') path = path + '/';
+  if (path[0] != '/') path = `/${path}`;
+  if (path[path.length - 1] != '/') path += '/';
   return path;
 };
diff --git a/packages/core/strapi/lib/utils/open-browser.js b/packages/core/strapi/lib/utils/open-browser.js
index 4f2702001f1..697a6ccd1e0 100644
--- a/packages/core/strapi/lib/utils/open-browser.js
+++ b/packages/core/strapi/lib/utils/open-browser.js
@@ -1,6 +1,6 @@
 'use strict';
 
-var open = require('open');
+const open = require('open');
 const { getAbsoluteAdminUrl } = require('@strapi/utils');
 
 async function openBrowser(config) {
diff --git a/packages/core/strapi/lib/utils/run-checks.js b/packages/core/strapi/lib/utils/run-checks.js
index 1a93dfc5163..6f9a3ec1eb5 100644
--- a/packages/core/strapi/lib/utils/run-checks.js
+++ b/packages/core/strapi/lib/utils/run-checks.js
@@ -5,8 +5,8 @@ const fs = require('fs-extra');
 
 const requiredPaths = ['api', 'extensions', 'plugins', 'config', 'public'];
 const checkFoldersExist = ({ appPath }) => {
-  let missingPaths = [];
-  for (let reqPath of requiredPaths) {
+  const missingPaths = [];
+  for (const reqPath of requiredPaths) {
     if (!fs.pathExistsSync(path.resolve(appPath, reqPath))) {
       missingPaths.push(reqPath);
     }
diff --git a/packages/core/strapi/lib/utils/startup-logger.js b/packages/core/strapi/lib/utils/startup-logger.js
index 214dd5c9c66..0b26dc919bb 100644
--- a/packages/core/strapi/lib/utils/startup-logger.js
+++ b/packages/core/strapi/lib/utils/startup-logger.js
@@ -23,7 +23,7 @@ module.exports = app => {
 
       infoTable.push(
         [chalk.blue('Time'), `${new Date()}`],
-        [chalk.blue('Launched in'), Date.now() - app.config.launchedAt + ' ms'],
+        [chalk.blue('Launched in'), `${Date.now() - app.config.launchedAt} ms`],
         [chalk.blue('Environment'), app.config.environment],
         [chalk.blue('Process PID'), process.pid],
         [chalk.blue('Version'), `${app.config.info.strapi} (node ${process.version})`],
diff --git a/packages/core/strapi/lib/utils/success.js b/packages/core/strapi/lib/utils/success.js
index 397656679d3..231442f0fbe 100644
--- a/packages/core/strapi/lib/utils/success.js
+++ b/packages/core/strapi/lib/utils/success.js
@@ -27,5 +27,5 @@ try {
     }).catch(() => {});
   }
 } catch (e) {
-  //...
+  // ...
 }
diff --git a/packages/core/strapi/tests/api/basic-compo-repeatable.test.e2e.js b/packages/core/strapi/tests/api/basic-compo-repeatable.test.e2e.js
index a4a8d54f8df..1eb9984f438 100644
--- a/packages/core/strapi/tests/api/basic-compo-repeatable.test.e2e.js
+++ b/packages/core/strapi/tests/api/basic-compo-repeatable.test.e2e.js
@@ -7,7 +7,7 @@ const { createContentAPIRequest } = require('../../../../../test/helpers/request
 const builder = createTestBuilder();
 let strapi;
 let rq;
-let data = {
+const data = {
   productsWithCompo: [],
 };
 
diff --git a/packages/core/strapi/tests/api/basic-compo.test.e2e.js b/packages/core/strapi/tests/api/basic-compo.test.e2e.js
index 6e7a3c5d2cd..757d4d5b6b4 100644
--- a/packages/core/strapi/tests/api/basic-compo.test.e2e.js
+++ b/packages/core/strapi/tests/api/basic-compo.test.e2e.js
@@ -7,7 +7,7 @@ const { createContentAPIRequest } = require('../../../../../test/helpers/request
 const builder = createTestBuilder();
 let strapi;
 let rq;
-let data = {
+const data = {
   productsWithCompo: [],
 };
 
diff --git a/packages/core/strapi/tests/api/basic-dp-compo-repeatable.test.e2e.js b/packages/core/strapi/tests/api/basic-dp-compo-repeatable.test.e2e.js
index c4d0b74ee2b..60f09fe1c4d 100644
--- a/packages/core/strapi/tests/api/basic-dp-compo-repeatable.test.e2e.js
+++ b/packages/core/strapi/tests/api/basic-dp-compo-repeatable.test.e2e.js
@@ -7,7 +7,7 @@ const { createContentAPIRequest } = require('../../../../../test/helpers/request
 const builder = createTestBuilder();
 let strapi;
 let rq;
-let data = {
+const data = {
   productsWithCompoAndDP: [],
 };
 
diff --git a/packages/core/strapi/tests/api/basic-dp-compo.test.e2e.js b/packages/core/strapi/tests/api/basic-dp-compo.test.e2e.js
index 613d6cbaae0..b72a6a3876b 100644
--- a/packages/core/strapi/tests/api/basic-dp-compo.test.e2e.js
+++ b/packages/core/strapi/tests/api/basic-dp-compo.test.e2e.js
@@ -7,7 +7,7 @@ const { createContentAPIRequest } = require('../../../../../test/helpers/request
 const builder = createTestBuilder();
 let strapi;
 let rq;
-let data = {
+const data = {
   productsWithCompoAndDP: [],
 };
 
diff --git a/packages/core/strapi/tests/api/basic-dp.test.e2e.js b/packages/core/strapi/tests/api/basic-dp.test.e2e.js
index 47785b0a5c4..84781a9287d 100644
--- a/packages/core/strapi/tests/api/basic-dp.test.e2e.js
+++ b/packages/core/strapi/tests/api/basic-dp.test.e2e.js
@@ -9,7 +9,7 @@ const { createContentAPIRequest } = require('../../../../../test/helpers/request
 const builder = createTestBuilder();
 let strapi;
 let rq;
-let data = {
+const data = {
   products: [],
 };
 
diff --git a/packages/core/strapi/tests/api/basic.test.e2e.js b/packages/core/strapi/tests/api/basic.test.e2e.js
index c332ea89dde..0e6603bd2cd 100644
--- a/packages/core/strapi/tests/api/basic.test.e2e.js
+++ b/packages/core/strapi/tests/api/basic.test.e2e.js
@@ -7,7 +7,7 @@ const { createContentAPIRequest } = require('../../../../../test/helpers/request
 const builder = createTestBuilder();
 let strapi;
 let rq;
-let data = {
+const data = {
   product: [],
 };
 
diff --git a/packages/core/strapi/tests/endpoint.test.e2e.js b/packages/core/strapi/tests/endpoint.test.e2e.js
index afc857e0bb4..96555874ee3 100644
--- a/packages/core/strapi/tests/endpoint.test.e2e.js
+++ b/packages/core/strapi/tests/endpoint.test.e2e.js
@@ -145,9 +145,7 @@ describe('Create Strapi API End to End', () => {
 
     test('Update article1 add tag2', async () => {
       const { id, attributes } = data.articles[0];
-      const entry = Object.assign({}, attributes, {
-        tags: [data.tags[1].id],
-      });
+      const entry = { ...attributes, tags: [data.tags[1].id] };
 
       cleanDate(entry);
 
@@ -174,7 +172,7 @@ describe('Create Strapi API End to End', () => {
 
     test('Update article1 add tag1 and tag3', async () => {
       const { id, attributes } = data.articles[0];
-      const entry = Object.assign({}, attributes);
+      const entry = { ...attributes };
       entry.tags = data.tags.map(t => t.id);
 
       cleanDate(entry);
@@ -202,7 +200,7 @@ describe('Create Strapi API End to End', () => {
     test('Update article1 remove one tag', async () => {
       const { id, attributes } = data.articles[0];
 
-      const entry = Object.assign({}, attributes);
+      const entry = { ...attributes };
       entry.tags = entry.tags.data.slice(1).map(t => t.id);
 
       cleanDate(entry);
@@ -229,9 +227,7 @@ describe('Create Strapi API End to End', () => {
 
     test('Update article1 remove all tag', async () => {
       const { id, attributes } = data.articles[0];
-      const entry = Object.assign({}, attributes, {
-        tags: [],
-      });
+      const entry = { ...attributes, tags: [] };
 
       cleanDate(entry);
 
@@ -338,9 +334,7 @@ describe('Create Strapi API End to End', () => {
 
     test('Update article1 with cat2', async () => {
       const { id, attributes } = data.articles[0];
-      const entry = Object.assign({}, attributes, {
-        category: data.categories[1].id,
-      });
+      const entry = { ...attributes, category: data.categories[1].id };
 
       cleanDate(entry);
 
@@ -389,9 +383,7 @@ describe('Create Strapi API End to End', () => {
     test('Update article2 with cat2', async () => {
       const { id, attributes } = data.articles[1];
 
-      const entry = Object.assign({}, attributes, {
-        category: data.categories[1].id,
-      });
+      const entry = { ...attributes, category: data.categories[1].id };
 
       cleanDate(entry);
 
@@ -419,7 +411,7 @@ describe('Create Strapi API End to End', () => {
     test('Update cat1 with article1', async () => {
       const { id, attributes } = data.categories[0];
 
-      const entry = Object.assign({}, attributes);
+      const entry = { ...attributes };
       entry.articles = data.categories[0].attributes.articles.data
         .map(a => a.id)
         .concat(data.articles[0].id);
@@ -590,9 +582,7 @@ describe('Create Strapi API End to End', () => {
 
     test('Update article1 with ref1', async () => {
       const { id, attributes } = data.articles[0];
-      const entry = Object.assign({}, attributes, {
-        reference: data.references[0].id,
-      });
+      const entry = { ...attributes, reference: data.references[0].id };
 
       cleanDate(entry);
 
diff --git a/packages/core/strapi/tests/filtering.test.e2e.js b/packages/core/strapi/tests/filtering.test.e2e.js
index 076d2e61d8c..3e575f5d4cf 100644
--- a/packages/core/strapi/tests/filtering.test.e2e.js
+++ b/packages/core/strapi/tests/filtering.test.e2e.js
@@ -1261,7 +1261,7 @@ describe('Filtering API', () => {
     });
 
     test('Combined filters', async () => {
-      let res = await rq({
+      const res = await rq({
         method: 'GET',
         url: '/products',
         qs: {
diff --git a/packages/core/strapi/tests/lifecycles/before-delete.test.e2e.js b/packages/core/strapi/tests/lifecycles/before-delete.test.e2e.js
index 0e986eb4402..f33ea982c2f 100644
--- a/packages/core/strapi/tests/lifecycles/before-delete.test.e2e.js
+++ b/packages/core/strapi/tests/lifecycles/before-delete.test.e2e.js
@@ -7,7 +7,7 @@ const { createContentAPIRequest } = require('../../../../../test/helpers/request
 let builder;
 let strapi;
 let rq;
-let data = {
+const data = {
   productsWithCompo: [],
 };
 
diff --git a/packages/core/strapi/tests/migrations/migration-draft-publish.test.e2e.js b/packages/core/strapi/tests/migrations/migration-draft-publish.test.e2e.js
index 224fe86a7e2..acd0abebe86 100644
--- a/packages/core/strapi/tests/migrations/migration-draft-publish.test.e2e.js
+++ b/packages/core/strapi/tests/migrations/migration-draft-publish.test.e2e.js
@@ -10,7 +10,7 @@ const modelsUtils = require('../../../../../test/helpers/models');
 let builder;
 let strapi;
 let rq;
-let data = {
+const data = {
   dogs: [],
 };
 const dogModel = {
@@ -76,7 +76,7 @@ describe('Migration - draft and publish', () => {
 
     describe('Enabling D&P on a content-type', () => {
       test('No publishedAt before enabling the feature', async () => {
-        let { body } = await rq({
+        const { body } = await rq({
           url: '/content-manager/collection-types/api::dog.dog',
           method: 'GET',
         });
@@ -105,7 +105,7 @@ describe('Migration - draft and publish', () => {
 
         await restart();
 
-        let { body } = await rq({
+        const { body } = await rq({
           method: 'GET',
           url: '/content-manager/collection-types/api::dog.dog',
         });
@@ -149,7 +149,7 @@ describe('Migration - draft and publish', () => {
         // drafts should have been deleted with the migration, so we remove them
         data.dogs = data.dogs.filter(dog => !_.isNil(dog.publishedAt));
 
-        let { body } = await rq({
+        const { body } = await rq({
           url: '/content-manager/collection-types/api::dog.dog',
           method: 'GET',
         });
diff --git a/packages/core/strapi/tests/migrations/migration-required-attribute.test.e2e.js b/packages/core/strapi/tests/migrations/migration-required-attribute.test.e2e.js
index 750b374412d..33b2e9832d3 100644
--- a/packages/core/strapi/tests/migrations/migration-required-attribute.test.e2e.js
+++ b/packages/core/strapi/tests/migrations/migration-required-attribute.test.e2e.js
@@ -8,7 +8,7 @@ const modelsUtils = require('../../../../../test/helpers/models');
 const builder = createTestBuilder();
 let strapi;
 let rq;
-let data = {
+const data = {
   dogs: [],
 };
 
@@ -63,7 +63,7 @@ describe('Migration - required attribute', () => {
 
   describe('Required: false -> true', () => {
     test('Can be null before migration', async () => {
-      let { body } = await rq({
+      const { body } = await rq({
         method: 'GET',
         url: '/content-manager/collection-types/api::dog.dog',
       });
diff --git a/packages/core/strapi/tests/migrations/migration-unique-attribute.test.e2e.js b/packages/core/strapi/tests/migrations/migration-unique-attribute.test.e2e.js
index a9fd43c4294..b66ef4204e2 100644
--- a/packages/core/strapi/tests/migrations/migration-unique-attribute.test.e2e.js
+++ b/packages/core/strapi/tests/migrations/migration-unique-attribute.test.e2e.js
@@ -8,7 +8,7 @@ const modelsUtils = require('../../../../../test/helpers/models');
 const builder = createTestBuilder();
 let strapi;
 let rq;
-let data = {
+const data = {
   dogs: [],
 };
 
@@ -63,7 +63,7 @@ describe('Migration - unique attribute', () => {
 
   describe('Unique: false -> true', () => {
     test('Can have duplicates before migration', async () => {
-      let { body } = await rq({
+      const { body } = await rq({
         url: '/content-manager/collection-types/api::dog.dog',
         method: 'GET',
       });
diff --git a/packages/core/strapi/tests/search.test.e2e.js b/packages/core/strapi/tests/search.test.e2e.js
index 5fd7432708a..b3dc06233e2 100644
--- a/packages/core/strapi/tests/search.test.e2e.js
+++ b/packages/core/strapi/tests/search.test.e2e.js
@@ -11,7 +11,7 @@ const {
 const builder = createTestBuilder();
 let rq;
 let strapi;
-let data = {
+const data = {
   bed: [],
 };
 
diff --git a/packages/core/strapi/tests/single-type.test.e2e.js b/packages/core/strapi/tests/single-type.test.e2e.js
index 3c5259c2bfb..5682f6b12d9 100644
--- a/packages/core/strapi/tests/single-type.test.e2e.js
+++ b/packages/core/strapi/tests/single-type.test.e2e.js
@@ -8,8 +8,8 @@ const { createTestBuilder } = require('../../../../test/helpers/builder');
 const builder = createTestBuilder();
 let strapi;
 let rq;
-let uid = 'single-type';
-let data = {};
+const uid = 'single-type';
+const data = {};
 
 const model = {
   kind: 'singleType',
diff --git a/packages/core/upload/server/controllers/admin-folder-file.js b/packages/core/upload/server/controllers/admin-folder-file.js
index 5584aff2813..dde093bc21c 100644
--- a/packages/core/upload/server/controllers/admin-folder-file.js
+++ b/packages/core/upload/server/controllers/admin-folder-file.js
@@ -118,7 +118,7 @@ module.exports = {
 
       if (existingFolders.length > 0) {
         // update folders' parent relation
-        const joinTable = strapi.db.metadata.get(FOLDER_MODEL_UID).attributes.parent.joinTable;
+        const { joinTable } = strapi.db.metadata.get(FOLDER_MODEL_UID).attributes.parent;
         await strapi.db
           .queryBuilder(joinTable.name)
           .transacting(trx)
diff --git a/packages/core/upload/server/graphql.js b/packages/core/upload/server/graphql.js
index 2fc6e7b8505..0922dfdb0d0 100644
--- a/packages/core/upload/server/graphql.js
+++ b/packages/core/upload/server/graphql.js
@@ -236,11 +236,11 @@ module.exports = ({ strapi }) => {
       types: [fileInfoInputType, mutations],
       resolversConfig: {
         // Use custom scopes for the upload file CRUD operations
-        ['Query.uploadFiles']: { auth: { scope: 'plugin::upload.content-api.find' } },
-        ['Query.uploadFile']: { auth: { scope: 'plugin::upload.content-api.findOne' } },
-        ['Mutation.createUploadFile']: { auth: { scope: 'plugin::upload.content-api.upload' } },
-        ['Mutation.updateUploadFile']: { auth: { scope: 'plugin::upload.content-api.upload' } },
-        ['Mutation.deleteUploadFile']: { auth: { scope: 'plugin::upload.content-api.destroy' } },
+        'Query.uploadFiles': { auth: { scope: 'plugin::upload.content-api.find' } },
+        'Query.uploadFile': { auth: { scope: 'plugin::upload.content-api.findOne' } },
+        'Mutation.createUploadFile': { auth: { scope: 'plugin::upload.content-api.upload' } },
+        'Mutation.updateUploadFile': { auth: { scope: 'plugin::upload.content-api.upload' } },
+        'Mutation.deleteUploadFile': { auth: { scope: 'plugin::upload.content-api.destroy' } },
 
         [`Mutation.${UPLOAD_MUTATION_NAME}`]: {
           auth: { scope: 'plugin::upload.content-api.upload' },
diff --git a/packages/core/upload/server/services/__tests__/folder.test.js b/packages/core/upload/server/services/__tests__/folder.test.js
index 6165931b004..c6308e2a7a0 100644
--- a/packages/core/upload/server/services/__tests__/folder.test.js
+++ b/packages/core/upload/server/services/__tests__/folder.test.js
@@ -4,7 +4,7 @@ const { setPathIdAndPath } = require('../folder');
 
 const folderUID = '1';
 const rootPathRegex = /^\/[0-9]*$/i;
-const folderPathRegex = new RegExp('^/' + folderUID + '/[0-9]*$', 'i');
+const folderPathRegex = new RegExp(`^/${folderUID}/[0-9]*$`, 'i');
 
 describe('folder', () => {
   describe('setPathIdAndPath', () => {
diff --git a/packages/core/upload/server/services/__tests__/metrics.js b/packages/core/upload/server/services/__tests__/metrics.js
index 8bb0a2016eb..8f19a7b617d 100644
--- a/packages/core/upload/server/services/__tests__/metrics.js
+++ b/packages/core/upload/server/services/__tests__/metrics.js
@@ -4,7 +4,7 @@ const metricsService = require('../metrics');
 
 // TODO: the matcher exists in jest@28
 const closeTo = (expected, precision = 2) => ({
-  asymmetricMatch: actual => Math.abs(expected - actual) < Math.pow(10, -precision) / 2,
+  asymmetricMatch: actual => Math.abs(expected - actual) < 10 ** -precision / 2,
 });
 
 describe('metrics', () => {
diff --git a/packages/core/upload/server/services/__tests__/upload/uploadImage.test.js b/packages/core/upload/server/services/__tests__/upload/uploadImage.test.js
index 6a6e572df66..d7e4473bb54 100644
--- a/packages/core/upload/server/services/__tests__/upload/uploadImage.test.js
+++ b/packages/core/upload/server/services/__tests__/upload/uploadImage.test.js
@@ -70,7 +70,7 @@ describe('Upload image', () => {
   });
 
   test('Upload with thubmnail', async () => {
-    let fileData = getFileData(imageFilePath);
+    const fileData = getFileData(imageFilePath);
     const upload = jest.fn();
     mockUploadProvider(upload);
 
@@ -79,7 +79,7 @@ describe('Upload image', () => {
   });
 
   test('Upload with responsive formats', async () => {
-    let fileData = getFileData(imageFilePath);
+    const fileData = getFileData(imageFilePath);
     const upload = jest.fn();
     mockUploadProvider(upload, { responsiveDimensions: true });
 
diff --git a/packages/core/upload/server/services/folder.js b/packages/core/upload/server/services/folder.js
index ebc70926687..49db2362b46 100644
--- a/packages/core/upload/server/services/folder.js
+++ b/packages/core/upload/server/services/folder.js
@@ -113,7 +113,7 @@ const update = async (id, { name, parent }, { user }) => {
         .execute();
 
       // update parent folder (delete + insert; upsert not possible)
-      const joinTable = strapi.db.metadata.get(FOLDER_MODEL_UID).attributes.parent.joinTable;
+      const { joinTable } = strapi.db.metadata.get(FOLDER_MODEL_UID).attributes.parent;
       await strapi.db
         .queryBuilder(joinTable.name)
         .transacting(trx)
@@ -207,7 +207,7 @@ const exists = async (params = {}) => {
  * @returns {Promise<array>}
  */
 const getStructure = async () => {
-  const joinTable = strapi.db.metadata.get(FOLDER_MODEL_UID).attributes.parent.joinTable;
+  const { joinTable } = strapi.db.metadata.get(FOLDER_MODEL_UID).attributes.parent;
   const qb = strapi.db.queryBuilder(FOLDER_MODEL_UID);
   const alias = qb.getAlias();
   const folders = await qb
diff --git a/packages/core/upload/server/services/image-manipulation.js b/packages/core/upload/server/services/image-manipulation.js
index 1828c3468e8..4bb4a2b2cd7 100644
--- a/packages/core/upload/server/services/image-manipulation.js
+++ b/packages/core/upload/server/services/image-manipulation.js
@@ -1,4 +1,5 @@
 'use strict';
+
 /**
  * Image manipulation functions
  */
@@ -111,7 +112,7 @@ const optimize = async file => {
 
   if (newSize > size) {
     // Ignore optimization if output is bigger than original
-    return Object.assign({}, file, { width, height, size: bytesToKbytes(size) });
+    return { ...file, width, height, size: bytesToKbytes(size) };
   }
 
   return Object.assign(newFile, {
diff --git a/packages/core/upload/server/services/metrics.js b/packages/core/upload/server/services/metrics.js
index bc03f34187e..67f08fd8b93 100644
--- a/packages/core/upload/server/services/metrics.js
+++ b/packages/core/upload/server/services/metrics.js
@@ -21,7 +21,7 @@ module.exports = ({ strapi }) => ({
     const folderTable = strapi.getModel(FOLDER_MODEL_UID).collectionName;
 
     let keepOnlySlashesSQLString = '??';
-    let queryParams = [pathColName];
+    const queryParams = [pathColName];
     for (let i = 0; i < 10; i += 1) {
       keepOnlySlashesSQLString = `REPLACE(${keepOnlySlashesSQLString}, ?, ?)`;
       queryParams.push(String(i), '');
diff --git a/packages/core/upload/server/utils/file.js b/packages/core/upload/server/utils/file.js
index beca4be3345..5b8d382eed3 100644
--- a/packages/core/upload/server/utils/file.js
+++ b/packages/core/upload/server/utils/file.js
@@ -1,4 +1,5 @@
 'use strict';
+
 /**
  * Utils file containing file treatment utils
  */
diff --git a/packages/core/upload/tests/admin/file-folder.test.e2e.js b/packages/core/upload/tests/admin/file-folder.test.e2e.js
index bcb8070ca61..98aa6c33d10 100644
--- a/packages/core/upload/tests/admin/file-folder.test.e2e.js
+++ b/packages/core/upload/tests/admin/file-folder.test.e2e.js
@@ -9,7 +9,7 @@ const { createAuthRequest } = require('../../../../../test/helpers/request');
 
 let strapi;
 let rq;
-let data = {
+const data = {
   folders: [],
   files: [],
 };
diff --git a/packages/core/upload/tests/admin/folder-file.test.e2e.js b/packages/core/upload/tests/admin/folder-file.test.e2e.js
index 1f9ce986244..ea1616da2db 100644
--- a/packages/core/upload/tests/admin/folder-file.test.e2e.js
+++ b/packages/core/upload/tests/admin/folder-file.test.e2e.js
@@ -9,7 +9,7 @@ const { createAuthRequest } = require('../../../../../test/helpers/request');
 
 let strapi;
 let rq;
-let data = {
+const data = {
   folders: [],
   files: [],
 };
diff --git a/packages/core/upload/tests/admin/folder-structure.test.e2e.js b/packages/core/upload/tests/admin/folder-structure.test.e2e.js
index 3ab8e239243..0a6bf2d945a 100644
--- a/packages/core/upload/tests/admin/folder-structure.test.e2e.js
+++ b/packages/core/upload/tests/admin/folder-structure.test.e2e.js
@@ -6,7 +6,7 @@ const { createAuthRequest } = require('../../../../../test/helpers/request');
 
 let strapi;
 let rq;
-let data = {
+const data = {
   folders: [],
 };
 
diff --git a/packages/core/upload/tests/admin/folder.test.e2e.js b/packages/core/upload/tests/admin/folder.test.e2e.js
index c4356f8d90a..7ef2ec2ce17 100644
--- a/packages/core/upload/tests/admin/folder.test.e2e.js
+++ b/packages/core/upload/tests/admin/folder.test.e2e.js
@@ -11,12 +11,12 @@ const { createAuthRequest } = require('../../../../../test/helpers/request');
 
 let strapi;
 let rq;
-let data = {
+const data = {
   folders: [],
 };
 
 const rootPathRegex = /^\/[0-9]*$/i;
-const getFolderPathRegex = pathId => new RegExp('^/' + pathId + '/[0-9]*$', 'i');
+const getFolderPathRegex = pathId => new RegExp(`^/${pathId}/[0-9]*$`, 'i');
 
 const createFolder = async (name, parent = null) => {
   const res = await rq({
diff --git a/packages/core/utils/lib/build-query.js b/packages/core/utils/lib/build-query.js
index 35c7f7da375..b2814cfe1dd 100644
--- a/packages/core/utils/lib/build-query.js
+++ b/packages/core/utils/lib/build-query.js
@@ -1,6 +1,6 @@
 'use strict';
 
-//TODO: move to dbal
+// TODO: move to dbal
 
 const _ = require('lodash');
 const parseType = require('./parse-type');
@@ -114,7 +114,8 @@ const normalizeWhereClauses = (whereClauses, { model }) => {
     .filter(({ field, value }) => {
       if (_.isNull(value)) {
         return false;
-      } else if (_.isUndefined(value)) {
+      }
+      if (_.isUndefined(value)) {
         strapi.log.warn(`The value of field: '${field}', in your where filter, is undefined.`);
         return false;
       }
diff --git a/packages/core/utils/lib/config.js b/packages/core/utils/lib/config.js
index 9a653aa4d92..26ea365fc6a 100644
--- a/packages/core/utils/lib/config.js
+++ b/packages/core/utils/lib/config.js
@@ -64,13 +64,13 @@ const getConfigUrls = (config, forAdminBuild = false) => {
 
 const getAbsoluteUrl = adminOrServer => (config, forAdminBuild = false) => {
   const { serverUrl, adminUrl } = getConfigUrls(config, forAdminBuild);
-  let url = adminOrServer === 'server' ? serverUrl : adminUrl;
+  const url = adminOrServer === 'server' ? serverUrl : adminUrl;
 
   if (url.startsWith('http')) {
     return url;
   }
 
-  let hostname =
+  const hostname =
     config.get('environment') === 'development' &&
     ['127.0.0.1', '0.0.0.0'].includes(config.get('server.host'))
       ? 'localhost'
diff --git a/packages/core/utils/lib/convert-query-params.js b/packages/core/utils/lib/convert-query-params.js
index 1640bc5de4d..6c4093175c6 100644
--- a/packages/core/utils/lib/convert-query-params.js
+++ b/packages/core/utils/lib/convert-query-params.js
@@ -336,12 +336,10 @@ const convertAndSanitizeFilters = (filters, schema) => {
     }
 
     // Handle operators
-    else {
-      if (['$null', '$notNull'].includes(key)) {
-        filters[key] = parseType({ type: 'boolean', value: filters[key], forceCast: true });
-      } else if (isObject(value)) {
-        filters[key] = convertAndSanitizeFilters(value, schema);
-      }
+    else if (['$null', '$notNull'].includes(key)) {
+      filters[key] = parseType({ type: 'boolean', value: filters[key], forceCast: true });
+    } else if (isObject(value)) {
+      filters[key] = convertAndSanitizeFilters(value, schema);
     }
 
     // Remove empty objects & arrays
diff --git a/packages/core/utils/lib/parse-type.js b/packages/core/utils/lib/parse-type.js
index f96052ebe93..bb6e0b03a01 100644
--- a/packages/core/utils/lib/parse-type.js
+++ b/packages/core/utils/lib/parse-type.js
@@ -26,7 +26,7 @@ const parseTime = value => {
 const parseDate = value => {
   if (dates.isDate(value)) return dates.format(value, 'yyyy-MM-dd');
   try {
-    let date = dates.parseISO(value);
+    const date = dates.parseISO(value);
 
     if (dates.isValid(date)) return dates.format(date, 'yyyy-MM-dd');
 
diff --git a/packages/core/utils/lib/policy.js b/packages/core/utils/lib/policy.js
index 5474e9c1ecb..7eec9c7adec 100644
--- a/packages/core/utils/lib/policy.js
+++ b/packages/core/utils/lib/policy.js
@@ -1,6 +1,7 @@
 /**
  * Policies util
  */
+
 'use strict';
 
 const _ = require('lodash');
diff --git a/packages/core/utils/lib/print-value.js b/packages/core/utils/lib/print-value.js
index 0645e99f619..ec258eed7de 100644
--- a/packages/core/utils/lib/print-value.js
+++ b/packages/core/utils/lib/print-value.js
@@ -3,7 +3,7 @@
 // Code copied from the yup library (https://github.com/jquense/yup)
 // https://github.com/jquense/yup/blob/2778b88bdacd5260d593c6468793da2e77daf21f/src/util/printValue.ts
 
-const toString = Object.prototype.toString;
+const { toString } = Object.prototype;
 const errorToString = Error.prototype.toString;
 const regExpToString = RegExp.prototype.toString;
 const symbolToString = typeof Symbol !== 'undefined' ? Symbol.prototype.toString : () => '';
@@ -13,34 +13,34 @@ const SYMBOL_REGEXP = /^Symbol\((.*)\)(.*)$/;
 function printNumber(val) {
   if (val != +val) return 'NaN';
   const isNegativeZero = val === 0 && 1 / val < 0;
-  return isNegativeZero ? '-0' : '' + val;
+  return isNegativeZero ? '-0' : `${val}`;
 }
 
 function printSimpleValue(val, quoteStrings = false) {
-  if (val == null || val === true || val === false) return '' + val;
+  if (val == null || val === true || val === false) return `${val}`;
 
   const typeOf = typeof val;
   if (typeOf === 'number') return printNumber(val);
   if (typeOf === 'string') return quoteStrings ? `"${val}"` : val;
-  if (typeOf === 'function') return '[Function ' + (val.name || 'anonymous') + ']';
+  if (typeOf === 'function') return `[Function ${val.name || 'anonymous'}]`;
   if (typeOf === 'symbol') return symbolToString.call(val).replace(SYMBOL_REGEXP, 'Symbol($1)');
 
   const tag = toString.call(val).slice(8, -1);
-  if (tag === 'Date') return isNaN(val.getTime()) ? '' + val : val.toISOString(val);
-  if (tag === 'Error' || val instanceof Error) return '[' + errorToString.call(val) + ']';
+  if (tag === 'Date') return isNaN(val.getTime()) ? `${val}` : val.toISOString(val);
+  if (tag === 'Error' || val instanceof Error) return `[${errorToString.call(val)}]`;
   if (tag === 'RegExp') return regExpToString.call(val);
 
   return null;
 }
 
 function printValue(value, quoteStrings) {
-  let result = printSimpleValue(value, quoteStrings);
+  const result = printSimpleValue(value, quoteStrings);
   if (result !== null) return result;
 
   return JSON.stringify(
     value,
     function(key, value) {
-      let result = printSimpleValue(this[key], quoteStrings);
+      const result = printSimpleValue(this[key], quoteStrings);
       if (result !== null) return result;
       return value;
     },
diff --git a/packages/core/utils/lib/sanitize/visitors/restricted-fields.js b/packages/core/utils/lib/sanitize/visitors/restricted-fields.js
index d3f1805d5f2..08232ea83a1 100644
--- a/packages/core/utils/lib/sanitize/visitors/restricted-fields.js
+++ b/packages/core/utils/lib/sanitize/visitors/restricted-fields.js
@@ -26,6 +26,5 @@ module.exports = (restrictedFields = null) => ({ key, path }, { remove }) => {
   );
   if (isRestrictedNested) {
     remove(key);
-    return;
   }
 };
diff --git a/packages/core/utils/lib/string-formatting.js b/packages/core/utils/lib/string-formatting.js
index dbef3c24132..a7969a8a433 100644
--- a/packages/core/utils/lib/string-formatting.js
+++ b/packages/core/utils/lib/string-formatting.js
@@ -1,4 +1,5 @@
 'use strict';
+
 const _ = require('lodash');
 const { trimChars, trimCharsEnd, trimCharsStart } = require('lodash/fp');
 const slugify = require('@sindresorhus/slugify');
diff --git a/packages/core/utils/lib/validators.js b/packages/core/utils/lib/validators.js
index 59d7a4381e9..dcce78cfc9b 100644
--- a/packages/core/utils/lib/validators.js
+++ b/packages/core/utils/lib/validators.js
@@ -87,11 +87,12 @@ const validateYupSchemaSync = (schema, options = {}) => (body, errorMessage) =>
 yup.setLocale({
   mixed: {
     notType({ path, type, value, originalValue }) {
-      let isCast = originalValue != null && originalValue !== value;
-      let msg =
+      const isCast = originalValue != null && originalValue !== value;
+      const msg =
         `${path} must be a \`${type}\` type, ` +
-        `but the final value was: \`${printValue(value, true)}\`` +
-        (isCast ? ` (cast from the value \`${printValue(originalValue, true)}\`).` : '.');
+        `but the final value was: \`${printValue(value, true)}\`${
+          isCast ? ` (cast from the value \`${printValue(originalValue, true)}\`).` : '.'
+        }`;
 
       /* Remove comment that is not supposed to be seen by the enduser
       if (value === null) {
diff --git a/packages/generators/admin/plopfile.js b/packages/generators/admin/plopfile.js
index 54b0f15d27c..629668e34e6 100644
--- a/packages/generators/admin/plopfile.js
+++ b/packages/generators/admin/plopfile.js
@@ -46,10 +46,9 @@ module.exports = function(
     if (arguments.length === 2) {
       const condition = arguments[0];
       return leftShift(condition ? fn(this) : inverse(this));
-    } else {
-      const [a, operator, b] = Array.from(arguments).slice(0, end);
-      return leftShift(evaluateExpression(a, operator, b) ? fn(this) : inverse(this));
     }
+    const [a, operator, b] = Array.from(arguments).slice(0, end);
+    return leftShift(evaluateExpression(a, operator, b) ? fn(this) : inverse(this));
   });
   plop.setHelper('unless', function(/* ...args, options */) {
     const end = arguments.length - 1;
@@ -57,10 +56,9 @@ module.exports = function(
     if (arguments.length === 2) {
       const condition = arguments[0];
       return leftShift(!condition ? fn(this) : inverse(this));
-    } else {
-      const [a, operator, b] = Array.from(arguments).slice(0, end);
-      return leftShift(!evaluateExpression(a, operator, b) ? fn(this) : inverse(this));
     }
+    const [a, operator, b] = Array.from(arguments).slice(0, end);
+    return leftShift(!evaluateExpression(a, operator, b) ? fn(this) : inverse(this));
   });
   plop.setHelper('else', function(_, { fn }) {
     return leftShift(fn(this));
diff --git a/packages/generators/app/lib/create-cli-db-project.js b/packages/generators/app/lib/create-cli-db-project.js
index 5c5f6eb9264..36caf473a15 100644
--- a/packages/generators/app/lib/create-cli-db-project.js
+++ b/packages/generators/app/lib/create-cli-db-project.js
@@ -12,7 +12,7 @@ module.exports = async scope => {
   console.log('Creating a project from the database CLI arguments.');
   await trackUsage({ event: 'didChooseCustomDatabase', scope });
 
-  const client = scope.database.client;
+  const { client } = scope.database;
   const configuration = {
     client: getClientName({ client }),
     connection: merge({}, defaultConfigs[client] || {}, scope.database),
diff --git a/packages/generators/app/lib/create-customized-project.js b/packages/generators/app/lib/create-customized-project.js
index 19fca39f8c8..e68dc08e41e 100644
--- a/packages/generators/app/lib/create-customized-project.js
+++ b/packages/generators/app/lib/create-customized-project.js
@@ -1,4 +1,5 @@
 /* eslint-disable no-unreachable */
+
 'use strict';
 
 const { join } = require('path');
@@ -151,8 +152,8 @@ async function askDatabaseInfos(scope) {
 }
 
 async function installDatabaseTestingDep({ scope, configuration }) {
-  let packageManager = scope.useYarn ? 'yarnpkg' : 'npm';
-  let cmd = scope.useYarn
+  const packageManager = scope.useYarn ? 'yarnpkg' : 'npm';
+  const cmd = scope.useYarn
     ? ['--cwd', scope.tmpPath, 'add']
     : ['install', '--prefix', scope.tmpPath];
 
diff --git a/packages/generators/app/lib/index.js b/packages/generators/app/lib/index.js
index 3fb6e42d42e..99bd327d4be 100644
--- a/packages/generators/app/lib/index.js
+++ b/packages/generators/app/lib/index.js
@@ -32,7 +32,7 @@ const generateNewApp = (projectDirectory, cliArguments) => {
     rootPath,
     name: basename(rootPath),
     // disable quickstart run app after creation
-    runQuickstartApp: cliArguments.run === false ? false : true,
+    runQuickstartApp: cliArguments.run !== false,
     // use pacakge version as strapiVersion (all packages have the same version);
     strapiVersion: require('../package.json').version,
     debug: cliArguments.debug !== undefined,
diff --git a/packages/generators/app/lib/resources/json/common/package.json.js b/packages/generators/app/lib/resources/json/common/package.json.js
index 7760415ddb5..e26fb4c8640 100644
--- a/packages/generators/app/lib/resources/json/common/package.json.js
+++ b/packages/generators/app/lib/resources/json/common/package.json.js
@@ -28,14 +28,13 @@ module.exports = opts => {
       strapi: 'strapi',
     },
     devDependencies: {},
-    dependencies: Object.assign(
-      {},
-      strapiDependencies.reduce((acc, key) => {
+    dependencies: {
+      ...strapiDependencies.reduce((acc, key) => {
         acc[key] = strapiVersion;
         return acc;
       }, {}),
-      additionalsDependencies
-    ),
+      ...additionalsDependencies,
+    },
     author: {
       name: 'A Strapi developer',
     },
diff --git a/packages/generators/app/lib/utils/check-requirements.js b/packages/generators/app/lib/utils/check-requirements.js
index 09e6a91ef84..8aee891e8f4 100644
--- a/packages/generators/app/lib/utils/check-requirements.js
+++ b/packages/generators/app/lib/utils/check-requirements.js
@@ -1,9 +1,9 @@
 'use strict';
 
 module.exports = function checkBeforeInstall() {
-  var currentNodeVersion = process.versions.node;
-  var semver = currentNodeVersion.split('.');
-  var major = semver[0];
+  const currentNodeVersion = process.versions.node;
+  const semver = currentNodeVersion.split('.');
+  const major = semver[0];
 
   if (major < 12) {
     console.error(`You are running Node ${currentNodeVersion}`);
diff --git a/packages/generators/app/lib/utils/usage.js b/packages/generators/app/lib/utils/usage.js
index 196c1c6b824..34745d4a3c8 100644
--- a/packages/generators/app/lib/utils/usage.js
+++ b/packages/generators/app/lib/utils/usage.js
@@ -21,7 +21,7 @@ async function captureException(error) {
     sentry.captureException(error);
     await sentry.flush();
   } catch (err) {
-    /** ignore errors*/
+    /** ignore errors */
     return Promise.resolve();
   }
 }
@@ -31,7 +31,7 @@ async function captureError(message) {
     sentry.captureMessage(message, 'error');
     await sentry.flush();
   } catch (err) {
-    /** ignore errors*/
+    /** ignore errors */
     return Promise.resolve();
   }
 }
@@ -69,7 +69,7 @@ function trackEvent(event, body) {
       headers: { 'Content-Type': 'application/json' },
     }).catch(() => {});
   } catch (err) {
-    /** ignore errors*/
+    /** ignore errors */
     return Promise.resolve();
   }
 }
@@ -78,7 +78,7 @@ function trackError({ scope, error }) {
   const { uuid } = scope;
 
   const properties = {
-    error: typeof error == 'string' ? error : error && error.message,
+    error: typeof error === 'string' ? error : error && error.message,
     os: os.type(),
     platform: os.platform(),
     release: os.release(),
@@ -97,7 +97,7 @@ function trackError({ scope, error }) {
       properties: addPackageJsonStrapiMetadata(properties, scope),
     });
   } catch (err) {
-    /** ignore errors*/
+    /** ignore errors */
     return Promise.resolve();
   }
 }
@@ -106,7 +106,7 @@ function trackUsage({ event, scope, error }) {
   const { uuid } = scope;
 
   const properties = {
-    error: typeof error == 'string' ? error : error && error.message,
+    error: typeof error === 'string' ? error : error && error.message,
     os: os.type(),
     os_platform: os.platform(),
     os_release: os.release(),
@@ -126,7 +126,7 @@ function trackUsage({ event, scope, error }) {
       properties: addPackageJsonStrapiMetadata(properties, scope),
     });
   } catch (err) {
-    /** ignore errors*/
+    /** ignore errors */
     return Promise.resolve();
   }
 }
diff --git a/packages/generators/generators/lib/plops/prompts/get-destination-prompts.js b/packages/generators/generators/lib/plops/prompts/get-destination-prompts.js
index 77d9c12b991..5f3fdb0a53e 100644
--- a/packages/generators/generators/lib/plops/prompts/get-destination-prompts.js
+++ b/packages/generators/generators/lib/plops/prompts/get-destination-prompts.js
@@ -1,4 +1,5 @@
 'use strict';
+
 const { join } = require('path');
 const fs = require('fs-extra');
 
diff --git a/packages/plugins/documentation/__tests__/build-component-schema.test.js b/packages/plugins/documentation/__tests__/build-component-schema.test.js
index e0f23dd2a64..ebbd1d6ac2a 100644
--- a/packages/plugins/documentation/__tests__/build-component-schema.test.js
+++ b/packages/plugins/documentation/__tests__/build-component-schema.test.js
@@ -79,8 +79,8 @@ describe('Build Component Schema', () => {
     }
 
     const schemaNames = Object.keys(schemas);
-    const pluginListResponseValue = schemas['UsersPermissionsRoleListResponse'];
-    const apiListResponseValue = schemas['RestaurantListResponse'];
+    const pluginListResponseValue = schemas.UsersPermissionsRoleListResponse;
+    const apiListResponseValue = schemas.RestaurantListResponse;
 
     const expectedShape = {
       type: 'object',
@@ -144,8 +144,8 @@ describe('Build Component Schema', () => {
     }
 
     const schemaNames = Object.keys(schemas);
-    const pluginListResponseValue = schemas['UsersPermissionsRoleRequest'];
-    const apiListResponseValue = schemas['RestaurantRequest'];
+    const pluginListResponseValue = schemas.UsersPermissionsRoleRequest;
+    const apiListResponseValue = schemas.RestaurantRequest;
 
     const expectedShape = {
       type: 'object',
@@ -192,8 +192,8 @@ describe('Build Component Schema', () => {
     }
 
     const schemaNames = Object.keys(schemas);
-    const pluginListResponseValue = schemas['UsersPermissionsRoleLocalizationResponse'];
-    const apiListResponseValue = schemas['RestaurantLocalizationResponse'];
+    const pluginListResponseValue = schemas.UsersPermissionsRoleLocalizationResponse;
+    const apiListResponseValue = schemas.RestaurantLocalizationResponse;
 
     const expectedShape = {
       type: 'object',
@@ -236,8 +236,8 @@ describe('Build Component Schema', () => {
     }
 
     const schemaNames = Object.keys(schemas);
-    const pluginListResponseValue = schemas['UsersPermissionsRoleLocalizationRequest'];
-    const apiListResponseValue = schemas['RestaurantLocalizationRequest'];
+    const pluginListResponseValue = schemas.UsersPermissionsRoleLocalizationRequest;
+    const apiListResponseValue = schemas.RestaurantLocalizationRequest;
 
     const expectedShape = {
       type: 'object',
diff --git a/packages/plugins/documentation/server/bootstrap.js b/packages/plugins/documentation/server/bootstrap.js
index d0dac9cd269..c2601c7a145 100755
--- a/packages/plugins/documentation/server/bootstrap.js
+++ b/packages/plugins/documentation/server/bootstrap.js
@@ -1,4 +1,5 @@
 /* eslint-disable no-unreachable */
+
 'use strict';
 
 // Add permissions
diff --git a/packages/plugins/documentation/server/routes/index.js b/packages/plugins/documentation/server/routes/index.js
index 6e8821e18f0..9a2ef067dec 100644
--- a/packages/plugins/documentation/server/routes/index.js
+++ b/packages/plugins/documentation/server/routes/index.js
@@ -1,4 +1,5 @@
 'use strict';
+
 const restrictAccess = require('../middlewares/restrict-access');
 
 module.exports = [
diff --git a/packages/plugins/documentation/server/services/helpers/build-api-endpoint-path.js b/packages/plugins/documentation/server/services/helpers/build-api-endpoint-path.js
index 156ae8bf7d1..c4409a0eeb3 100644
--- a/packages/plugins/documentation/server/services/helpers/build-api-endpoint-path.js
+++ b/packages/plugins/documentation/server/services/helpers/build-api-endpoint-path.js
@@ -20,7 +20,7 @@ const parsePathWithVariables = routePath => {
     .parse(routePath)
     .map(token => {
       if (_.isObject(token)) {
-        return token.prefix + '{' + token.name + '}';
+        return `${token.prefix}{${token.name}}`;
       }
 
       return token;
diff --git a/packages/plugins/documentation/server/services/helpers/build-component-schema.js b/packages/plugins/documentation/server/services/helpers/build-component-schema.js
index e245bddeb70..d3ed8458948 100644
--- a/packages/plugins/documentation/server/services/helpers/build-component-schema.js
+++ b/packages/plugins/documentation/server/services/helpers/build-component-schema.js
@@ -1,4 +1,5 @@
 'use strict';
+
 const _ = require('lodash');
 
 const cleanSchemaAttributes = require('./utils/clean-schema-attributes');
diff --git a/packages/plugins/documentation/server/services/helpers/utils/loop-content-type-names.js b/packages/plugins/documentation/server/services/helpers/utils/loop-content-type-names.js
index 67d37b46d39..aa2f7000870 100644
--- a/packages/plugins/documentation/server/services/helpers/utils/loop-content-type-names.js
+++ b/packages/plugins/documentation/server/services/helpers/utils/loop-content-type-names.js
@@ -1,4 +1,5 @@
 'use strict';
+
 const _ = require('lodash');
 
 /**
diff --git a/packages/plugins/graphql/server/services/builders/entity-meta.js b/packages/plugins/graphql/server/services/builders/entity-meta.js
index 4d7c3aff492..8a525ca130d 100644
--- a/packages/plugins/graphql/server/services/builders/entity-meta.js
+++ b/packages/plugins/graphql/server/services/builders/entity-meta.js
@@ -1,6 +1,6 @@
 'use strict';
 
-function buildEntityMetaDefinition(/*contentType*/) {}
+function buildEntityMetaDefinition(/* contentType */) {}
 
 module.exports = () => ({
   buildEntityMetaDefinition,
diff --git a/packages/plugins/graphql/server/services/builders/resolvers/association.js b/packages/plugins/graphql/server/services/builders/resolvers/association.js
index cb9006b674a..3d996924183 100644
--- a/packages/plugins/graphql/server/services/builders/resolvers/association.js
+++ b/packages/plugins/graphql/server/services/builders/resolvers/association.js
@@ -72,7 +72,7 @@ module.exports = ({ strapi }) => {
 
         // If this is a to-many relation, it returns an object that
         // matches what the entity-response-collection's resolvers expect
-        else if (isToMany) {
+        if (isToMany) {
           return toEntityResponseCollection(data, info);
         }
 
diff --git a/packages/plugins/graphql/server/services/builders/type.js b/packages/plugins/graphql/server/services/builders/type.js
index 24202aeade4..55cb3dde25e 100644
--- a/packages/plugins/graphql/server/services/builders/type.js
+++ b/packages/plugins/graphql/server/services/builders/type.js
@@ -130,7 +130,7 @@ module.exports = context => {
     const { buildAssociationResolver } = getGraphQLService('builders').get('content-api');
     const extension = getGraphQLService('extension');
 
-    let { builder } = options;
+    const { builder } = options;
     const { attributeName, attribute, contentType } = options;
     const fileUID = 'plugin::upload.file';
 
@@ -207,7 +207,7 @@ module.exports = context => {
     const { buildAssociationResolver } = getGraphQLService('builders').get('content-api');
     const extension = getGraphQLService('extension');
 
-    let { builder } = options;
+    const { builder } = options;
     const { attributeName, attribute, contentType } = options;
 
     if (extension.shadowCRUD(attribute.target).isDisabled()) {
diff --git a/packages/plugins/graphql/server/services/builders/utils.js b/packages/plugins/graphql/server/services/builders/utils.js
index cb6c15f30a3..214d1eb77c6 100644
--- a/packages/plugins/graphql/server/services/builders/utils.js
+++ b/packages/plugins/graphql/server/services/builders/utils.js
@@ -35,7 +35,7 @@ module.exports = ({ strapi }) => {
       }
 
       // Collection Types
-      else if (kind === 'collectionType') {
+      if (kind === 'collectionType') {
         if (!multiple) {
           return { id: 'ID' };
         }
@@ -54,7 +54,7 @@ module.exports = ({ strapi }) => {
       }
 
       // Single Types
-      else if (kind === 'singleType') {
+      if (kind === 'singleType') {
         const params = {};
 
         if (hasDraftAndPublish(contentType)) {
diff --git a/packages/plugins/graphql/server/services/internals/scalars/time.js b/packages/plugins/graphql/server/services/internals/scalars/time.js
index 06134f2fd95..201d9b2fa2f 100644
--- a/packages/plugins/graphql/server/services/internals/scalars/time.js
+++ b/packages/plugins/graphql/server/services/internals/scalars/time.js
@@ -27,7 +27,7 @@ const TimeScalar = new GraphQLScalarType({
       throw new ValidationError('Time cannot represent non string type');
     }
 
-    const value = ast.value;
+    const { value } = ast;
 
     return parseType({ type: 'time', value });
   },
diff --git a/packages/plugins/graphql/tests/crud.test.e2e.js b/packages/plugins/graphql/tests/crud.test.e2e.js
index e8873debdbd..57dffdc559a 100644
--- a/packages/plugins/graphql/tests/crud.test.e2e.js
+++ b/packages/plugins/graphql/tests/crud.test.e2e.js
@@ -61,7 +61,7 @@ describe('Test Graphql API End to End', () => {
       { name: 'post 1', bigint: 1316130638171, nullable: 'value', category: 'BLOG' },
       { name: 'post 2', bigint: 1416130639261, nullable: null, category: 'PRODUCT' },
     ];
-    let data = {
+    const data = {
       posts: [],
     };
 
@@ -487,7 +487,7 @@ describe('Test Graphql API End to End', () => {
     });
 
     test('Delete Posts', async () => {
-      for (let post of data.posts) {
+      for (const post of data.posts) {
         const res = await graphqlQuery({
           query: /* GraphQL */ `
             mutation deletePost($id: ID!) {
diff --git a/packages/plugins/graphql/tests/relations.test.e2e.js b/packages/plugins/graphql/tests/relations.test.e2e.js
index 51047fc89ae..08ed8f30b53 100644
--- a/packages/plugins/graphql/tests/relations.test.e2e.js
+++ b/packages/plugins/graphql/tests/relations.test.e2e.js
@@ -134,7 +134,7 @@ describe('Test Graphql Relations API End to End', () => {
   });
 
   describe('Test relations features', () => {
-    let data = {
+    const data = {
       labels: [],
       documents: [],
       people: [],
@@ -488,7 +488,7 @@ describe('Test Graphql Relations API End to End', () => {
     });
 
     test('Delete Labels and test Documents relations', async () => {
-      for (let label of data.labels) {
+      for (const label of data.labels) {
         const res = await graphqlQuery({
           query: /* GraphQL */ `
             mutation deleteLabel($id: ID!) {
@@ -579,7 +579,7 @@ describe('Test Graphql Relations API End to End', () => {
     });
 
     test('Delete Documents', async () => {
-      for (let document of data.documents) {
+      for (const document of data.documents) {
         const res = await graphqlQuery({
           query: /* GraphQL */ `
             mutation deleteDocument($id: ID!) {
diff --git a/packages/plugins/i18n/server/constants/__tests__/index.test.js b/packages/plugins/i18n/server/constants/__tests__/index.test.js
index 81121547663..e0618330c62 100644
--- a/packages/plugins/i18n/server/constants/__tests__/index.test.js
+++ b/packages/plugins/i18n/server/constants/__tests__/index.test.js
@@ -1,6 +1,6 @@
 'use strict';
 
-const { getInitLocale } = require('../');
+const { getInitLocale } = require('..');
 
 describe('I18N default locale', () => {
   describe('getInitLocale', () => {
diff --git a/packages/plugins/i18n/server/controllers/content-types.js b/packages/plugins/i18n/server/controllers/content-types.js
index e1bbd7e4c06..d6db512ab1a 100644
--- a/packages/plugins/i18n/server/controllers/content-types.js
+++ b/packages/plugins/i18n/server/controllers/content-types.js
@@ -34,7 +34,7 @@ module.exports = {
       throw new ApplicationError('model.not.localized');
     }
 
-    let params = modelDef.kind === 'singleType' ? {} : { id };
+    const params = modelDef.kind === 'singleType' ? {} : { id };
 
     const entity = await strapi
       .query(model)
diff --git a/packages/plugins/i18n/server/controllers/locales.js b/packages/plugins/i18n/server/controllers/locales.js
index 1e48113cbe0..9f7ec74a791 100644
--- a/packages/plugins/i18n/server/controllers/locales.js
+++ b/packages/plugins/i18n/server/controllers/locales.js
@@ -57,7 +57,7 @@ module.exports = {
     const { user } = ctx.state;
     const { id } = ctx.params;
     const { body } = ctx.request;
-    let { isDefault, ...updates } = body;
+    const { isDefault, ...updates } = body;
 
     await validateUpdateLocaleInput(body);
 
diff --git a/packages/plugins/i18n/server/graphql.js b/packages/plugins/i18n/server/graphql.js
index e6105196f01..b2bffd337e2 100644
--- a/packages/plugins/i18n/server/graphql.js
+++ b/packages/plugins/i18n/server/graphql.js
@@ -209,7 +209,7 @@ module.exports = ({ strapi }) => ({
           return;
         }
 
-        const contentType = registryType.config.contentType;
+        const { contentType } = registryType.config;
 
         // Ignore non-localized content types
         if (!isLocalizedContentType(contentType)) {
diff --git a/packages/plugins/i18n/server/migrations/field/migrate-for-bookshelf.js b/packages/plugins/i18n/server/migrations/field/migrate-for-bookshelf.js
index 3f9852ef106..17c9f76c80b 100644
--- a/packages/plugins/i18n/server/migrations/field/migrate-for-bookshelf.js
+++ b/packages/plugins/i18n/server/migrations/field/migrate-for-bookshelf.js
@@ -16,7 +16,7 @@ const batchInsertInTmpTable = async ({ updatesInfo }, { transacting: trx }) => {
 };
 
 const updateFromTmpTable = async ({ model, attributesToMigrate }, { transacting: trx }) => {
-  const collectionName = model.collectionName;
+  const { collectionName } = model;
   if (model.client === 'pg') {
     const substitutes = attributesToMigrate.map(() => '?? = ??.??').join(',');
     const bindings = [collectionName];
diff --git a/packages/plugins/i18n/server/services/__tests__/core-api.test.js b/packages/plugins/i18n/server/services/__tests__/core-api.test.js
index 31bcff9c92b..2ede2f120a9 100644
--- a/packages/plugins/i18n/server/services/__tests__/core-api.test.js
+++ b/packages/plugins/i18n/server/services/__tests__/core-api.test.js
@@ -1,4 +1,5 @@
 'use strict';
+
 const { createSanitizer } = require('../core-api')();
 
 describe('Core API', () => {
diff --git a/packages/plugins/i18n/server/services/__tests__/entity-service-decorator.test.js b/packages/plugins/i18n/server/services/__tests__/entity-service-decorator.test.js
index fc809381a6a..ec2379b4b28 100644
--- a/packages/plugins/i18n/server/services/__tests__/entity-service-decorator.test.js
+++ b/packages/plugins/i18n/server/services/__tests__/entity-service-decorator.test.js
@@ -134,7 +134,7 @@ describe('Entity service decorator', () => {
         };
         const service = decorator(defaultService);
 
-        const input = Object.assign({ populate: ['test'], ...params });
+        const input = { populate: ['test'], ...params };
         const output = await service.wrapParams(input, { uid: 'test-model', action });
 
         expect(output).toEqual({ populate: ['test'], ...params });
diff --git a/packages/plugins/i18n/server/services/__tests__/metrics.test.js b/packages/plugins/i18n/server/services/__tests__/metrics.test.js
index c6f7af29519..341e921ee73 100644
--- a/packages/plugins/i18n/server/services/__tests__/metrics.test.js
+++ b/packages/plugins/i18n/server/services/__tests__/metrics.test.js
@@ -28,7 +28,7 @@ describe('Metrics', () => {
       plugins: {
         i18n: {
           services: {
-            ['content-types']: {
+            'content-types': {
               isLocalizedContentType,
             },
           },
diff --git a/packages/plugins/i18n/server/services/content-types.js b/packages/plugins/i18n/server/services/content-types.js
index 6c17568d002..1e6a34080c8 100644
--- a/packages/plugins/i18n/server/services/content-types.js
+++ b/packages/plugins/i18n/server/services/content-types.js
@@ -203,7 +203,7 @@ const getNestedPopulateOfNonLocalizedAttributes = modelUID => {
   const currentAttributesToPopulate = difference(nonLocalizedAttributes, scalarAttributes);
   const attributesToPopulate = [...currentAttributesToPopulate];
 
-  for (let attrName of currentAttributesToPopulate) {
+  for (const attrName of currentAttributesToPopulate) {
     const attr = schema.attributes[attrName];
     if (attr.type === 'component') {
       const nestedPopulate = getNestedPopulateOfNonLocalizedAttributes(attr.component).map(
diff --git a/packages/plugins/i18n/server/services/locales.js b/packages/plugins/i18n/server/services/locales.js
index 4841573ff47..67fa8546854 100644
--- a/packages/plugins/i18n/server/services/locales.js
+++ b/packages/plugins/i18n/server/services/locales.js
@@ -58,10 +58,9 @@ const setIsDefault = async locales => {
 
   if (Array.isArray(locales)) {
     return locales.map(locale => ({ ...locale, isDefault: actualDefault === locale.code }));
-  } else {
-    // single locale
-    return { ...locales, isDefault: actualDefault === locales.code };
   }
+  // single locale
+  return { ...locales, isDefault: actualDefault === locales.code };
 };
 
 const initDefaultLocale = async () => {
diff --git a/packages/plugins/i18n/tests/content-manager/list-relation.test.e2e.js b/packages/plugins/i18n/tests/content-manager/list-relation.test.e2e.js
index 601c58d2317..e64abcc963e 100644
--- a/packages/plugins/i18n/tests/content-manager/list-relation.test.e2e.js
+++ b/packages/plugins/i18n/tests/content-manager/list-relation.test.e2e.js
@@ -8,7 +8,7 @@ const { createAuthRequest } = require('../../../../../test/helpers/request');
 
 let strapi;
 let rq;
-let data = {
+const data = {
   products: [],
   shops: [],
 };
diff --git a/packages/plugins/i18n/tests/locales.test.e2e.js b/packages/plugins/i18n/tests/locales.test.e2e.js
index 4afed3fb403..b7a4823f09f 100644
--- a/packages/plugins/i18n/tests/locales.test.e2e.js
+++ b/packages/plugins/i18n/tests/locales.test.e2e.js
@@ -56,7 +56,7 @@ describe('CRUD locales', () => {
 
   describe('Default locale', () => {
     test('Default locale is already created', async () => {
-      let res = await rq({
+      const res = await rq({
         url: '/i18n/locales',
         method: 'GET',
       });
@@ -76,7 +76,7 @@ describe('CRUD locales', () => {
         isDefault: false,
       };
 
-      let res = await rq({
+      const res = await rq({
         url: '/i18n/locales',
         method: 'POST',
         body: locale,
@@ -95,7 +95,7 @@ describe('CRUD locales', () => {
         name: 'Italian',
       };
 
-      let res = await rq({
+      const res = await rq({
         url: '/i18n/locales',
         method: 'POST',
         body: locale,
@@ -133,7 +133,7 @@ describe('CRUD locales', () => {
         isDefault: false,
       };
 
-      let res = await rq({
+      const res = await rq({
         url: '/i18n/locales',
         method: 'POST',
         body: locale,
@@ -158,7 +158,7 @@ describe('CRUD locales', () => {
         isDefault: false,
       };
 
-      let res = await rq({
+      const res = await rq({
         url: '/i18n/locales',
         method: 'POST',
         body: locale,
@@ -209,7 +209,7 @@ describe('CRUD locales', () => {
 
   describe('Read', () => {
     test('Can list the locales', async () => {
-      let res = await rq({
+      const res = await rq({
         url: '/i18n/locales',
         method: 'GET',
       });
@@ -229,7 +229,7 @@ describe('CRUD locales', () => {
         isDefault: false,
       };
 
-      let res = await rq({
+      const res = await rq({
         url: `/i18n/locales/${data.locales[1].id}`,
         method: 'PUT',
         body: localeUpdate,
@@ -248,7 +248,7 @@ describe('CRUD locales', () => {
         code: 'ak',
       };
 
-      let res = await rq({
+      const res = await rq({
         url: `/i18n/locales/${data.locales[0].id}`,
         method: 'PUT',
         body: localeUpdate,
@@ -280,7 +280,7 @@ describe('CRUD locales', () => {
         code: 'ak',
       };
 
-      let res = await rq({
+      const res = await rq({
         url: `/i18n/locales/${data.locales[0].id}`,
         method: 'PUT',
         body: localeUpdate,
@@ -450,7 +450,7 @@ describe('CRUD locales', () => {
     });
 
     test('Cannot delete not found locale', async () => {
-      let res = await rq({
+      const res = await rq({
         url: `/i18n/locales/${data.deletedLocales[0].id}`,
         method: 'DELETE',
       });
diff --git a/packages/plugins/sentry/server/services/sentry/index.js b/packages/plugins/sentry/server/services/sentry/index.js
index 8755ae8ddd1..617b08715c3 100644
--- a/packages/plugins/sentry/server/services/sentry/index.js
+++ b/packages/plugins/sentry/server/services/sentry/index.js
@@ -1,4 +1,5 @@
 'use strict';
+
 // FIXME
 /* eslint-disable import/extensions */
 const Sentry = require('@sentry/node');
diff --git a/packages/plugins/users-permissions/server/controllers/auth.js b/packages/plugins/users-permissions/server/controllers/auth.js
index 19c0c4863ac..3ac4c560756 100644
--- a/packages/plugins/users-permissions/server/controllers/auth.js
+++ b/packages/plugins/users-permissions/server/controllers/auth.js
@@ -326,7 +326,7 @@ module.exports = {
       }
     }
 
-    let newUser = {
+    const newUser = {
       ...params,
       role: role.id,
       email: email.toLowerCase(),
diff --git a/packages/plugins/users-permissions/server/controllers/settings.js b/packages/plugins/users-permissions/server/controllers/settings.js
index f4475bc19cd..0fed222d5b9 100644
--- a/packages/plugins/users-permissions/server/controllers/settings.js
+++ b/packages/plugins/users-permissions/server/controllers/settings.js
@@ -17,7 +17,7 @@ module.exports = {
 
     const emailTemplates = ctx.request.body['email-templates'];
 
-    for (let key in emailTemplates) {
+    for (const key in emailTemplates) {
       const template = emailTemplates[key].options.message;
 
       if (!isValidEmailTemplate(template)) {
diff --git a/packages/plugins/users-permissions/server/controllers/user.js b/packages/plugins/users-permissions/server/controllers/user.js
index 94b7d424212..0f685738eb1 100644
--- a/packages/plugins/users-permissions/server/controllers/user.js
+++ b/packages/plugins/users-permissions/server/controllers/user.js
@@ -121,7 +121,7 @@ module.exports = {
       ctx.request.body.email = ctx.request.body.email.toLowerCase();
     }
 
-    let updateData = {
+    const updateData = {
       ...ctx.request.body,
     };
 
diff --git a/packages/plugins/users-permissions/server/controllers/validation/email-template.js b/packages/plugins/users-permissions/server/controllers/validation/email-template.js
index 8f3581d7b10..0a2bd1672f0 100644
--- a/packages/plugins/users-permissions/server/controllers/validation/email-template.js
+++ b/packages/plugins/users-permissions/server/controllers/validation/email-template.js
@@ -28,7 +28,7 @@ const matchAll = (pattern, src) => {
 };
 
 const isValidEmailTemplate = template => {
-  for (let reg of invalidPatternsRegexes) {
+  for (const reg of invalidPatternsRegexes) {
     if (reg.test(template)) {
       return false;
     }
diff --git a/packages/plugins/users-permissions/server/middlewares/rateLimit.js b/packages/plugins/users-permissions/server/middlewares/rateLimit.js
index c35f3b6c9e3..09716806e32 100644
--- a/packages/plugins/users-permissions/server/middlewares/rateLimit.js
+++ b/packages/plugins/users-permissions/server/middlewares/rateLimit.js
@@ -14,17 +14,12 @@ module.exports = (config, { strapi }) => async (ctx, next) => {
     },
   ];
 
-  return ratelimit.middleware(
-    Object.assign(
-      {},
-      {
-        interval: 1 * 60 * 1000,
-        max: 5,
-        prefixKey: `${ctx.request.path}:${ctx.request.ip}`,
-        message,
-      },
-      strapi.config.get('plugin.users-permissions.ratelimit'),
-      config
-    )
-  )(ctx, next);
+  return ratelimit.middleware({
+    interval: 1 * 60 * 1000,
+    max: 5,
+    prefixKey: `${ctx.request.path}:${ctx.request.ip}`,
+    message,
+    ...strapi.config.get('plugin.users-permissions.ratelimit'),
+    ...config,
+  })(ctx, next);
 };
diff --git a/packages/plugins/users-permissions/server/register.js b/packages/plugins/users-permissions/server/register.js
index 21d7151a461..35c7f3d8ee9 100644
--- a/packages/plugins/users-permissions/server/register.js
+++ b/packages/plugins/users-permissions/server/register.js
@@ -1,4 +1,5 @@
 'use strict';
+
 const fs = require('fs');
 const path = require('path');
 
diff --git a/packages/plugins/users-permissions/server/services/providers-registry.js b/packages/plugins/users-permissions/server/services/providers-registry.js
index bdd07d939a9..7bd8ac9548c 100644
--- a/packages/plugins/users-permissions/server/services/providers-registry.js
+++ b/packages/plugins/users-permissions/server/services/providers-registry.js
@@ -12,7 +12,7 @@ const getInitialProviders = ({ purest }) => ({
       .request()
       .then(({ body }) => {
         // Combine username and discriminator because discord username is not unique
-        var username = `${body.username}#${body.discriminator}`;
+        const username = `${body.username}#${body.discriminator}`;
         return {
           username,
           email: body.email,
@@ -264,7 +264,7 @@ const getInitialProviders = ({ purest }) => ({
           : body.strapiemail || body.email;
         if (!username || !email) {
           strapi.log.warn(
-            'CAS Response Body did not contain required attributes: ' + JSON.stringify(body)
+            `CAS Response Body did not contain required attributes: ${JSON.stringify(body)}`
           );
         }
         return {
diff --git a/packages/plugins/users-permissions/server/services/user.js b/packages/plugins/users-permissions/server/services/user.js
index d9e96b10ce4..3a99a745a39 100644
--- a/packages/plugins/users-permissions/server/services/user.js
+++ b/packages/plugins/users-permissions/server/services/user.js
@@ -99,7 +99,7 @@ module.exports = ({ strapi }) => ({
 
     const settings = await pluginStore
       .get({ key: 'email' })
-      .then(storeEmail => storeEmail['email_confirmation'].options);
+      .then(storeEmail => storeEmail.email_confirmation.options);
 
     // Sanitize the template's user information
     const sanitizedUserInfo = await sanitize.sanitizers.defaultSanitizeOutput(userSchema, user);
diff --git a/packages/plugins/users-permissions/server/strategies/users-permissions.js b/packages/plugins/users-permissions/server/strategies/users-permissions.js
index 88b556fce93..48d6bf4562e 100644
--- a/packages/plugins/users-permissions/server/strategies/users-permissions.js
+++ b/packages/plugins/users-permissions/server/strategies/users-permissions.js
@@ -77,7 +77,7 @@ const verify = async (auth, config) => {
     }
   }
 
-  let allowedActions = auth.allowedActions;
+  let { allowedActions } = auth;
 
   if (!allowedActions) {
     const permissions = await strapi.query('plugin::users-permissions.permission').findMany({
diff --git a/packages/plugins/users-permissions/tests/admin/roles-api.test.e2e.js b/packages/plugins/users-permissions/tests/admin/roles-api.test.e2e.js
index 68f4c10a874..85cebc1c2bf 100644
--- a/packages/plugins/users-permissions/tests/admin/roles-api.test.e2e.js
+++ b/packages/plugins/users-permissions/tests/admin/roles-api.test.e2e.js
@@ -7,17 +7,17 @@ const { createAuthRequest } = require('../../../../../test/helpers/request');
 
 let strapi;
 let rq;
-let data = {};
-let internals = {
+const data = {};
+const internals = {
   role: {
     name: 'Test Role',
     description: 'Some random test role',
   },
 };
 
-/*****************************
+/** ***************************
  * TESTS
- *****************************/
+ **************************** */
 describe('Roles API', () => {
   beforeAll(async () => {
     strapi = await createStrapiInstance();
diff --git a/packages/providers/email-amazon-ses/lib/index.js b/packages/providers/email-amazon-ses/lib/index.js
index bd12fd4ddb1..13244ee114f 100644
--- a/packages/providers/email-amazon-ses/lib/index.js
+++ b/packages/providers/email-amazon-ses/lib/index.js
@@ -5,14 +5,14 @@ const { removeUndefined } = require('@strapi/utils');
 
 module.exports = {
   init(providerOptions = {}, settings = {}) {
-    var client = nodeSES.createClient({ ...providerOptions });
+    const client = nodeSES.createClient({ ...providerOptions });
 
     return {
       send(options) {
         return new Promise((resolve, reject) => {
           const { from, to, cc, bcc, replyTo, subject, text, html, ...rest } = options;
 
-          let msg = {
+          const msg = {
             from: from || settings.defaultFrom,
             to,
             cc,
diff --git a/packages/providers/email-mailgun/lib/index.js b/packages/providers/email-mailgun/lib/index.js
index cebe153b690..57ffd34b02e 100644
--- a/packages/providers/email-mailgun/lib/index.js
+++ b/packages/providers/email-mailgun/lib/index.js
@@ -35,7 +35,7 @@ module.exports = {
       send(options) {
         const { from, to, cc, bcc, replyTo, subject, text, html, ...rest } = options;
 
-        let data = {
+        const data = {
           from: from || settings.defaultFrom,
           to,
           cc,
diff --git a/packages/providers/email-sendgrid/lib/index.js b/packages/providers/email-sendgrid/lib/index.js
index 5ad3b9572a0..9aa7088bb25 100644
--- a/packages/providers/email-sendgrid/lib/index.js
+++ b/packages/providers/email-sendgrid/lib/index.js
@@ -12,7 +12,7 @@ module.exports = {
         return new Promise((resolve, reject) => {
           const { from, to, cc, bcc, replyTo, subject, text, html, ...rest } = options;
 
-          let msg = {
+          const msg = {
             from: from || settings.defaultFrom,
             to,
             cc,
diff --git a/packages/providers/email-sendmail/lib/index.js b/packages/providers/email-sendmail/lib/index.js
index 3b7499ec685..d2a8b13dec0 100644
--- a/packages/providers/email-sendmail/lib/index.js
+++ b/packages/providers/email-sendmail/lib/index.js
@@ -14,7 +14,7 @@ module.exports = {
         return new Promise((resolve, reject) => {
           const { from, to, cc, bcc, replyTo, subject, text, html, ...rest } = options;
 
-          let msg = {
+          const msg = {
             from: from || settings.defaultFrom,
             to,
             cc,
diff --git a/packages/utils/logger/lib/formats/log-errors.js b/packages/utils/logger/lib/formats/log-errors.js
index 60c1b6b527d..73a1bb5fecf 100644
--- a/packages/utils/logger/lib/formats/log-errors.js
+++ b/packages/utils/logger/lib/formats/log-errors.js
@@ -4,9 +4,7 @@ const { format } = require('winston');
 
 module.exports = format(info => {
   if (info instanceof Error) {
-    return Object.assign({}, info, {
-      message: `${info.message}${info.stack ? `\n` + info.stack : ''}`,
-    });
+    return { ...info, message: `${info.message}${info.stack ? `\n${info.stack}` : ''}` };
   }
 
   return info;
diff --git a/packages/utils/typescript/lib/generators/schemas/utils.js b/packages/utils/typescript/lib/generators/schemas/utils.js
index b6942551da6..41bcbbb7313 100644
--- a/packages/utils/typescript/lib/generators/schemas/utils.js
+++ b/packages/utils/typescript/lib/generators/schemas/utils.js
@@ -42,7 +42,7 @@ const getSchemaInterfaceName = pipe(replace(/(:.)/, ' '), camelCase, upperFirst)
 const getSchemaExtendsTypeName = schema => {
   const base = getSchemaModelType(schema);
 
-  return upperFirst(base) + 'Schema';
+  return `${upperFirst(base)}Schema`;
 };
 
 const getSchemaModelType = schema => {
@@ -54,7 +54,7 @@ const getSchemaModelType = schema => {
   }
 
   // Content-Types
-  else if (modelType === 'contentType') {
+  if (modelType === 'contentType') {
     return kind;
   }
 
diff --git a/packages/utils/typescript/lib/utils/resolve-outdir.js b/packages/utils/typescript/lib/utils/resolve-outdir.js
index cdeba7fd709..b9e090b57de 100644
--- a/packages/utils/typescript/lib/utils/resolve-outdir.js
+++ b/packages/utils/typescript/lib/utils/resolve-outdir.js
@@ -1,4 +1,5 @@
 'use strict';
+
 const path = require('path');
 const resolveConfigOptions = require('./resolve-config-options');
 const isUsingTypescript = require('./is-using-typescript');
diff --git a/scripts/front/add-missing-keys-to-other-language.js b/scripts/front/add-missing-keys-to-other-language.js
index 184f27f0ed6..d573052ab03 100644
--- a/scripts/front/add-missing-keys-to-other-language.js
+++ b/scripts/front/add-missing-keys-to-other-language.js
@@ -4,6 +4,7 @@
 //   node scripts/front/add-missing-keys-to-other-language.js [language]
 // Example:
 //   node scripts/front/add-missing-keys-to-other-language.js vi
+
 'use strict';
 
 const { join, dirname } = require('path');
diff --git a/scripts/front/merge-duplicated-translations/index.js b/scripts/front/merge-duplicated-translations/index.js
index b0dcf6697da..b9ceac4c730 100644
--- a/scripts/front/merge-duplicated-translations/index.js
+++ b/scripts/front/merge-duplicated-translations/index.js
@@ -1,4 +1,5 @@
 /* eslint-disable node/no-extraneous-require */
+
 'use strict';
 
 const path = require('path');
@@ -122,7 +123,7 @@ const merge = async valuesToMerge => {
   let current = 1;
   let mergedCount = 0;
 
-  for (let valueGroup of valuesToMerge) {
+  for (const valueGroup of valuesToMerge) {
     // Display
     console.clear();
     console.log(`${current}/${valuesToMerge.length}`);
diff --git a/scripts/front/utils/translation-files.js b/scripts/front/utils/translation-files.js
index 773be49a972..29ed909e09e 100644
--- a/scripts/front/utils/translation-files.js
+++ b/scripts/front/utils/translation-files.js
@@ -18,7 +18,7 @@ const readTranslationFile = filePath => ({
 });
 
 const writeTranslationFile = file => {
-  fs.writeFileSync(file.filePath, JSON.stringify(file.fileContent, null, 2) + '\n');
+  fs.writeFileSync(file.filePath, `${JSON.stringify(file.fileContent, null, 2)}\n`);
 };
 
 const readAllTranslationFiles = () => {
diff --git a/test/helpers/builder/index.js b/test/helpers/builder/index.js
index b6fc43120eb..78943894854 100644
--- a/test/helpers/builder/index.js
+++ b/test/helpers/builder/index.js
@@ -21,7 +21,7 @@ const createTestBuilder = (options = {}) => {
     },
 
     async sanitizedFixtures(strapi) {
-      const fixtures = this.fixtures;
+      const { fixtures } = this;
 
       for (const key of Object.keys(fixtures)) {
         fixtures[key] = await this.sanitizedFixturesFor(key, strapi);
diff --git a/test/helpers/strapi.js b/test/helpers/strapi.js
index 5a0aea6b654..b53c8a4da5f 100644
--- a/test/helpers/strapi.js
+++ b/test/helpers/strapi.js
@@ -36,9 +36,7 @@ const createStrapiInstance = async ({
       authenticate() {
         return { authenticated: true };
       },
-      verify() {
-        return;
-      },
+      verify() {},
     });
   }
   await instance.load();