.eslintrc.js

/* eslint-env node */

module.exports = {
  root: true,
  parser: "@typescript-eslint/parser",
  // do not extend `plugin:prettier/recommended` globally. it enables eslint-plugin-prettier which does not place nice with svelte currently.
  // prettier is enabled below for typescript files only
  // see https://github.com/sveltejs/prettier-plugin-svelte/issues/57
  extends: [
    "eslint:recommended",
    "plugin:@typescript-eslint/recommended",
    "plugin:unicorn/recommended",
  ],
  parserOptions: {
    ecmaVersion: 2020,
    sourceType: "module",
  },
  env: {
    browser: true,
    es6: true,
  },
  rules: {
    radix: "error",
    "require-await": "error",
    eqeqeq: "error",
    "unicorn/filename-case": [
      "error",
      {
        cases: {
          camelCase: true,
          pascalCase: true,
          kebabCase: true,
        },
      },
    ],
    "unicorn/number-literal-case": "off",
    "unicorn/no-array-reduce": "off",
  },
  overrides: [
    {
      files: ["*.ts", "*.js"],
      extends: [
        // running import plugin on svelte files is slow 🐢
        // therefore enable it for typescript only
        "plugin:import/errors",
        "plugin:import/warnings",
        "plugin:import/typescript",
        "plugin:prettier/recommended",
      ],
      rules: {
        "import/no-duplicates": "error",
        "prettier/prettier": "error",
      },
      settings: {
        "import/extensions": [".js", ".ts"],
      },
    },
    {
      files: ["*.test.ts"],
      rules: {
        "@typescript-eslint/no-explicit-any": "off",
      },
    },
    {
      files: ["*.config.js"],
      env: {
        node: true,
      },
    },
    {
      files: ["*.svelte"],
      extends: ["plugin:svelte/recommended"],
      parser: "svelte-eslint-parser",
      parserOptions: {
        parser: {
          ts: "@typescript-eslint/parser",
          typescript: "@typescript-eslint/parser",
        },
      },
    },
  ],
};