.eslintrc.json

{
  "root": true,
  "parser": "@typescript-eslint/parser",
  "parserOptions": {
    "ecmaVersion": "latest",
    "sourceType": "module",
    "project": true
  },
  "extends": [
    "next",
    "prettier",
    "plugin:import/recommended",
    "plugin:@typescript-eslint/recommended",
    "plugin:import/typescript"
  ],
  "plugins": [
    "@typescript-eslint",
    "simple-import-sort",
    "unused-imports",
    "import"
  ],
  "settings": {
    "import/resolver": {
      "typescript": {
        "alwaysTryTypes": true,
        "project": "."
      }
    }
  },
  "rules": {
    /** Only single quotes **/
    "quotes": ["error", "single", { "avoidEscape": true }],
    /** We live to remove this rule. */
    "@typescript-eslint/no-explicit-any": "off",
    /** We do too much of this with the singletons */
    "import/no-anonymous-default-export": "off",

    /** No absolute imports */
    "import/no-absolute-path": "error",

    /** Ensures all imports appear before other statements */
    "import/first": ["error"],

    /** Ensures there’s an empty line between imports and other statements */
    "import/newline-after-import": ["warn", { "count": 1 }],

    /** Sorts imports automatically */
    "simple-import-sort/imports": "warn",

    /** We only use namespaces in our generated types and those are not in our control */
    "@typescript-eslint/no-namespace": "off",

    /** Ensures no unused imports are present, and only _ prefixed variables can be unused */
    "no-unused-vars": "off",
    "unused-imports/no-unused-vars": [
      "warn",
      {
        "vars": "all",
        "varsIgnorePattern": "^_",
        "args": "after-used",
        "argsIgnorePattern": "^_"
      }
    ],
    "unused-imports/no-unused-imports": "error",
    "@typescript-eslint/no-misused-promises": "off",

    "no-restricted-syntax": [
      "warn",
      {
        "selector": "TSEnumDeclaration",
        "message": "Don’t declare enums! Use string literal unions instead, they’re safer and more ergonomic."
      }
    ],

    "@typescript-eslint/no-unnecessary-condition": "warn",
    "@typescript-eslint/no-unnecessary-type-arguments": "warn",
    "@typescript-eslint/prefer-for-of": "warn",
    "@typescript-eslint/prefer-function-type": "warn",

    "@typescript-eslint/no-confusing-non-null-assertion": "error",

    /** Standardises arrays. Simple arrays use brackets, complex arrays uses generic syntax
     * @example - ❌ `const foo: Array<string> = [];`
     * @example - ✅ `const foo: string[] = [];`
     * @example - ❌ `const foo: ReturnType<typeof bar>[] = [];`
     * @example - ✅ `const foo: Array<ReturnType<typeof bar>> = [];`
     */
    "@typescript-eslint/array-type": ["warn"],

    /** Enforces generics on the cunstructor, not as type annotation.
     * @example - ❌ `const foo: Foo<string> = new Foo();`
     * @example - ✅ `const foo = new Foo<string>();`
     */
    "@typescript-eslint/consistent-generic-constructors": [
      "warn",
      "constructor"
    ],

    /** Prefer Record<X,Y> over {[key: X]: Y} syntax */
    "@typescript-eslint/consistent-indexed-object-style": ["warn", "record"],

    /** Already handled by unused-imports */
    "@typescript-eslint/no-unused-vars": "off",

    /** React uses that a lot */
    "@typescript-eslint/unbound-method": "off",

    "@typescript-eslint/ban-ts-comment": [
      "error",
      {
        "ts-expect-error": "allow-with-description",
        "ts-ignore": true,
        "ts-nocheck": true,
        "ts-check": false,
        "minimumDescriptionLength": 5
      }
    ],

    "no-restricted-imports": [
      "error",
      {
        "paths": [
          /** Prevents us from using global lodash imports that break tree-shaking */
          {
            "name": "lodash",
            "message": "Import [module] from lodash/[module] instead"
          }
        ]
      }
    ],
    "react/jsx-curly-brace-presence": [
      "warn",
      {
        "props": "never",
        "children": "never"
      }
    ],
    "object-curly-spacing": ["warn", "always"]
  }
}