.eslintrc.js

/**
 * @license
 * Copyright 2024 Google LLC
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

module.exports = {
  env: {
    browser: true,
    es6: true,
    node: true,
  },
  parser: "@typescript-eslint/parser",
  plugins: [
    "@typescript-eslint",
    "@typescript-eslint/tslint",
    "import",
    "unused-imports",
  ],
  parserOptions: {
    ecmaVersion: 2015,
    sourceType: "module",
    project: "tsconfig.json",
  },
  overrides: [
    {
      files: ["**/*.test.ts", "**/{test,testing}/**/*.ts"],
      rules: {
        // TODO: Use https://www.npmjs.com/package/eslint-plugin-chai-friendly instead
        "no-unused-expressions": "off",
        "@typescript-eslint/no-explicit-any": "off",
      },
    },
  ],
  ignorePatterns: ["dist/", ".eslintrc.js"],
  rules: {
    curly: ["error", "all"],
    "guard-for-in": "error",
    "no-extra-label": "error",
    "no-unused-labels": "error",
    "new-parens": "error",
    "no-new-wrappers": "error",
    "no-debugger": "error",
    "no-duplicate-case": "error",
    "no-throw-literal": "error",
    "no-return-await": "error",
    "no-unsafe-finally": "error",
    "no-unused-expressions": [
      "error",
      {
        allowShortCircuit: true,
      },
    ],
    "no-var": "error",
    "object-shorthand": "error",
    "prefer-arrow-callback": [
      "error",
      {
        allowNamedFunctions: true,
      },
    ],
    "prefer-const": [
      "error",
      {
        destructuring: "all",
      },
    ],
    radix: "error",
    "unused-imports/no-unused-imports-ts": "error",
    "default-case": "error",
    eqeqeq: [
      "error",
      "always",
      {
        null: "ignore",
      },
    ],
    "no-caller": "error",
    "no-cond-assign": ["error", "always"],
    "use-isnan": "error",
    "constructor-super": "error",
    "no-restricted-properties": [
      "error",
      {
        object: "it",
        property: "skip",
      },
      {
        object: "it",
        property: "only",
      },
      {
        object: "describe",
        property: "skip",
      },
      {
        object: "describe",
        property: "only",
      },
      {
        object: "xit",
      },
    ],
    "no-restricted-globals": [
      "error",
      { name: "xit" },
      { name: "xdescribe" },
      { name: "parseInt", message: "tsstyle#type-coercion" },
      { name: "parseFloat", message: "tsstyle#type-coercion" },
    ],
    "no-array-constructor": "error",
    "sort-imports": [
      "error",
      {
        ignoreCase: false,
        ignoreDeclarationSort: true, // don't want to sort import lines, use eslint-plugin-import instead
        ignoreMemberSort: false,
        memberSyntaxSortOrder: ["none", "all", "multiple", "single"],
        allowSeparatedGroups: true,
      },
    ],
    "import/no-default-export": "error",
    "import/no-duplicates": "error",
    "import/no-extraneous-dependencies": [
      "error",
      {
        packageDir: [__dirname],
        peerDependencies: true,
      },
    ],
    "@typescript-eslint/array-type": [
      "error",
      {
        default: "array-simple",
      },
    ],
    "@typescript-eslint/ban-types": [
      "error",
      {
        types: {
          Object: "Use {} or 'object' instead.",
          String: "Use 'string' instead.",
          Number: "Use 'number' instead.",
          Boolean: "Use 'boolean' instead.",
          Function: `Avoid the Function type, as it provides little safety for the following reasons:
                       It provides no type safety when calling the value, which means it's easy to provide the wrong arguments.
                       It accepts class declarations, which will fail when called, as they are called without the new keyword.`,
        },
        extendDefaults: false,
      },
    ],
    "@typescript-eslint/naming-convention": [
      "error",
      {
        selector: "class",
        format: ["PascalCase"],
      },
      {
        selector: "interface",
        format: ["PascalCase"],
        custom: {
          regex: "^I[A-Z]",
          match: false,
        },
        leadingUnderscore: "allow",
      },
    ],
    "@typescript-eslint/consistent-type-definitions": ["error", "interface"],
    "@typescript-eslint/explicit-member-accessibility": [
      "error",
      {
        accessibility: "no-public",
        overrides: {
          parameterProperties: "off",
        },
      },
    ],
    "@typescript-eslint/consistent-type-assertions": [
      "error",
      {
        assertionStyle: "as",
      },
    ],
    "@typescript-eslint/no-explicit-any": ["error", { ignoreRestArgs: true }],
    "@typescript-eslint/no-namespace": [
      "error",
      {
        allowDeclarations: true,
      },
    ],
    "@typescript-eslint/triple-slash-reference": [
      "error",
      {
        path: "never",
        types: "never",
        lib: "never",
      },
    ],
    "@typescript-eslint/no-require-imports": "error",
    "@typescript-eslint/no-useless-constructor": "error",
    "@typescript-eslint/semi": "error",
    "@typescript-eslint/explicit-function-return-type": [
      "error",
      {
        allowExpressions: true,
        allowTypedFunctionExpressions: true,
        allowHigherOrderFunctions: true,
      },
    ],
    "@typescript-eslint/no-unused-vars": [
      "error",
      {
        varsIgnorePattern: "^_",
        argsIgnorePattern: "^_",
      },
    ],
    "@typescript-eslint/no-floating-promises": "error",
    "@typescript-eslint/tslint/config": [
      "error",
      {
        rules: {
          "jsdoc-format": true,
          "arrow-return-shorthand": true,
        },
      },
    ],
  },
};