Add rules and plugins to ESLint (mdn#16370)

* Add ESLint (using Standard styling)

* Add ESLint to npm run lint command

* Update package-lock.json

* Place ESLint after test/lint

* Add ESLint to fix command

* Update ESLint rules

* Use semicolons for separate commands

* Fix ESLint quotation rule

* Add TypeScript files in root to ESLint rules

* Run Prettier formatting

* Tell ESLint not to conflict with Prettier

* Fix security audit

* Disable no-console ESLint rule

* Let Prettier handle indenations

* Integrate ESLint into linter/fix scripts

* Fix bad merge

* Update ESLint

* Integrate Prettier into ESLint

* Remove stdio: inherit and force colors

* Lint JSDoc comments

* Label changes to .eslintrc.json as infra

* Install eslint-plugin-jsdoc as a dev dependency

* Allow empty catch block in try-catch

* Require JSDoc for any function/method/class

* Separate Prettier call for Markdown files

* Warn when function has no description

* Add JSDoc to format fix script

* Prefer arrow function syntax

* Fix formatting for TypeScript files

* Update JSDocs

* Update ESLint and its dependencies

* Add additional rules and sort alphabetically

* Prefer const over let

* Update package-lock.json

* Update package-lock.json

* Fix commands

* Fix commands

* Update eslint-plugin-jsdoc

* Fix typo

* Use TS no-extra-parens rule

* Run fix script

* Update quotes rule to avoid escapes

* Convert to arrow functions; update some typedefs

* Prefer typescript-eslint rule extensions

* Make fix script asynchronous

* Run fix script and manually fix many issues

* Require some JSDoc declarations

* Fix more issues

* Use prefer-arrow-functions plugin

* Run fix script

* Remove no-extra-parens rule (conflicts with Prettier)

* Disable default-case

* Fix remaining issues

* Silence warnings in fix script

* Update rules

* Fix remaining errors

* Fix TypeScript issues

.eslintrc.json

@@ -4,11 +4,17 @@
     "jest": true,
     "node": true
   },
-  "plugins": ["@typescript-eslint", "prettier"],
+  "plugins": [
+    "@typescript-eslint",
+    "prettier",
+    "jsdoc",
+    "prefer-arrow-functions"
+  ],
   "extends": [
     "eslint:recommended",
     "plugin:@typescript-eslint/recommended",
-    "plugin:prettier/recommended"
+    "plugin:prettier/recommended",
+    "plugin:jsdoc/recommended"
   ],
   "globals": {
     "Atomics": "readonly",
@@ -20,7 +26,50 @@
     "sourceType": "module"
   },
   "rules": {
+    "@typescript-eslint/no-explicit-any": "off",
+    "@typescript-eslint/no-unused-expressions": "error",
+    "@typescript-eslint/quotes": ["error", "single", { "avoidEscape": true }],
+    "consistent-return": "error",
+    "curly": "error",
+    "default-case": "off",
+    "default-case-last": "error",
+    "jsdoc/check-param-names": "error",
+    "jsdoc/require-description": "warn",
+    "jsdoc/require-jsdoc": [
+      "warn",
+      {
+        "require": {
+          "ArrowFunctionExpression": true,
+          "ClassDeclaration": true,
+          "ClassExpression": true,
+          "FunctionDeclaration": true,
+          "FunctionExpression": true,
+          "MethodDefinition": true
+        }
+      }
+    ],
+    "jsdoc/require-param-type": "error",
+    "jsdoc/require-returns": "error",
+    "jsdoc/require-returns-type": "error",
+    "jsdoc/no-undefined-types": "error",
+    "jsdoc/require-yields": "error",
+    "linebreak-style": ["error", "unix"],
+    "no-console": "off",
+    "no-else-return": "error",
+    "no-empty": ["error", { "allowEmptyCatch": true }],
+    "no-eval": "error",
+    "no-labels": "error",
+    "no-lone-blocks": "error",
+    "no-return-assign": "error",
+    "no-self-compare": "error",
+    "no-unused-expressions": "off",
+    "no-useless-call": "error",
+    "prefer-arrow-functions/prefer-arrow-functions": [
+      "error",
+      { "returnStyle": "implicit" }
+    ],
+    "prefer-const": "error",
     "prettier/prettier": "error",
-    "@typescript-eslint/no-explicit-any": "off"
+    "quotes": "off"
   }
 }

index.ts

@@ -20,7 +20,7 @@ const dirname = fileURLToPath(new URL('.', import.meta.url));
  * @param {string[]} dirs The directories to load
  * @returns {object} All of the browser compatibility data
  */
-async function load(...dirs: string[]) {
+const load = async (...dirs: string[]) => {
   const result = {};
 
   for (const dir of dirs) {
@@ -38,7 +38,9 @@ async function load(...dirs: string[]) {
         // Add source_file props
         const walker = walk(undefined, contents);
         for (const { compat } of walker) {
-          if (!compat) continue;
+          if (!compat) {
+            continue;
+          }
 
           compat.source_file = normalizePath(path.relative(dirname, fp));
         }
@@ -52,7 +54,7 @@ async function load(...dirs: string[]) {
   }
 
   return result;
-}
+};
 
 export default (await load(
   'api',

package.json

@@ -50,7 +50,9 @@
     "eslint-config-prettier": "~8.5.0",
     "eslint-config-standard": "~17.0.0",
     "eslint-plugin-import": "~2.26.0",
+    "eslint-plugin-jsdoc": "~39.3.4",
     "eslint-plugin-node": "~11.1.0",
+    "eslint-plugin-prefer-arrow-functions": "~3.1.4",
     "eslint-plugin-prettier": "~4.2.1",
     "eslint-plugin-promise": "~6.0.0",
     "fast-json-stable-stringify": "~2.1.0",
@@ -71,7 +73,7 @@
     "unittest": "c8 mocha index.test.ts --recursive \"{,!(node_modules)/**}/*.test.ts\"",
     "coverage": "c8 report -r lcov && open-cli coverage/lcov-report/index.html",
     "format": "npx eslint \"**/*.ts\" && npx prettier --check \"**/*.md\" \"**/*.json\"",
-    "format:fix": "npx eslint --fix \"**/*.ts\" && npx prettier --write \"**/*.md\" \"**/*.json\"",
+    "format:fix": "npx eslint --quiet --fix \"**/*.ts\" && npx prettier --write \"**/*.md\" \"**/*.json\"",
     "lint": "ts-node test/lint.ts",
     "fix": "npm run format:fix && ts-node scripts/fix/index.ts",
     "stats": "ts-node scripts/statistics.ts",