.eslintrc.json

{
  "extends": [
    "eslint:recommended",
    "plugin:@typescript-eslint/eslint-recommended",
    "plugin:@typescript-eslint/recommended"
  ],
  "parser": "@typescript-eslint/parser",
  "parserOptions": {
    "ecmaVersion": 2020,
    "sourceType": "module"
  },
  "plugins": [
    "eslint-plugin-import",
    "eslint-plugin-no-only-tests",
    "@typescript-eslint"
  ],
  "env": {
    "browser": true
  },
  "rules": {
    "import/extensions": ["error", "always"],
    "no-prototype-builtins": "off",
    "no-only-tests/no-only-tests": "error",
    "@typescript-eslint/ban-types": "off",
    "@typescript-eslint/explicit-module-boundary-types": "off",
    "@typescript-eslint/no-empty-function": "off",
    "@typescript-eslint/no-explicit-any": "error",
    "@typescript-eslint/no-non-null-assertion": "off",
    "@typescript-eslint/no-unused-vars": [
      "warn",
      {
        "argsIgnorePattern": "^_"
      }
    ],
    // Enforces that when a module is imported, that module is listed in the
    // package's immediate "dependencies". Note internal-only files are excluded
    // in an "overrides" configuration below.
    "import/no-extraneous-dependencies": [
      "error",
      {
        // These modules are also allowed to import from their immediate
        // "devDependencies".
        "devDependencies": [
          // This package has a type-only import of "react", but it's not a
          // dependency.
          "packages/labs/react/**"
        ]
      }
    ]
  },
  "overrides": [
    {
      "files": [
        "check-version-tracker.js",
        "rollup-common.js",
        "rollup.config.js",
        "web-test-runner.config.js"
      ],
      "env": {
        "node": true
      }
    },
    {
      "files": ["packages/lit-html/src/test/version-stability_test.js"],
      "env": {
        "mocha": true
      }
    },
    {
      "files": [
        "*_test.ts",
        "packages/labs/ssr/custom_typings/node.d.ts",
        "packages/labs/ssr/src/test/integration/tests/**",
        "packages/labs/ssr/src/lib/util/parse5-utils.ts"
      ],
      "rules": {
        "@typescript-eslint/no-explicit-any": "off"
      }
    },
    {
      // Files listed here don't need to declare their imports in their
      // immediate package.json "dependencies". This should include all
      // internal-only files, like tests, which are allowed to import from
      // "devDependencies", and also from packages declared only in the root
      // monorepo "package.json".
      "files": [
        "**/goldens/**",
        "**/rollup.config.js",
        "**/src/test-gen/**",
        "**/src/test/**",
        "**/src/tests/**",
        "**/test-output/**",
        "**/web-test-runner.config.js",
        "packages/benchmarks/**",
        "packages/labs/ssr/src/demo/**",
        "packages/tests/**",
        "rollup-common.js"
      ],
      "rules": {
        "import/no-extraneous-dependencies": "off"
      }
    }
  ]
}