Add linting

Author: benjie

.eslintignore

@@ -0,0 +1,2 @@
+/node_modules
+/dist

.eslintrc.js

@@ -0,0 +1,90 @@
+module.exports = {
+  parser: "@typescript-eslint/parser",
+  extends: [
+    "eslint:recommended",
+    "plugin:@typescript-eslint/eslint-recommended",
+    "plugin:@typescript-eslint/recommended",
+    "plugin:import/errors",
+    "plugin:import/typescript",
+    "prettier",
+  ],
+  plugins: ["@typescript-eslint", "simple-import-sort", "import"],
+  parserOptions: {
+    ecmaVersion: 2018,
+    sourceType: "module",
+  },
+  env: {
+    node: true,
+    es6: true,
+  },
+  globals: {
+    NodeJS: false, // For TypeScript
+  },
+  rules: {
+    "no-unused-vars": 0,
+    "@typescript-eslint/no-unused-vars": [
+      "error",
+      {
+        argsIgnorePattern: "^_",
+        varsIgnorePattern: "^_",
+        args: "after-used",
+        ignoreRestSiblings: true,
+      },
+    ],
+    curly: "error",
+    "no-else-return": 0,
+    "no-return-assign": [2, "except-parens"],
+    "no-underscore-dangle": 0,
+    camelcase: 0,
+    "prefer-arrow-callback": [
+      "error",
+      {
+        allowNamedFunctions: true,
+      },
+    ],
+    "class-methods-use-this": 0,
+    "no-restricted-syntax": 0,
+    "no-param-reassign": [
+      "error",
+      {
+        props: false,
+      },
+    ],
+
+    "arrow-body-style": 0,
+    "no-nested-ternary": 0,
+
+    /*
+     * simple-import-sort seems to be the most stable import sorting currently,
+     * disable others
+     */
+    "simple-import-sort/imports": "error",
+    "simple-import-sort/exports": "error",
+    "sort-imports": "off",
+    "import/order": "off",
+
+    "import/no-deprecated": "warn",
+    "import/no-duplicates": "error",
+    // Doesn't support 'exports'?
+    "import/no-unresolved": "off",
+    "@typescript-eslint/ban-ts-comment": "off",
+    "@typescript-eslint/no-namespace": "off",
+  },
+  overrides: [
+    {
+      files: ["__tests__/**/*", "test.js"],
+      rules: {
+        "@typescript-eslint/no-explicit-any": 0,
+        "@typescript-eslint/explicit-function-return-type": 0,
+        "@typescript-eslint/no-var-requires": 0,
+        "@typescript-eslint/ban-ts-comment": 0,
+      },
+    },
+    {
+      files: ["perfTest/**/*", "examples/**/*"],
+      rules: {
+        "@typescript-eslint/no-var-requires": 0,
+      },
+    },
+  ],
+};

package.json

@@ -9,7 +9,10 @@
   },
   "scripts": {
     "test": "node --test",
-    "watch": "tsc --watch"
+    "watch": "tsc --watch",
+    "lint": "yarn prettier:check && eslint --ext .js,.jsx,.ts,.tsx,.graphql .",
+    "lint:fix": "eslint --ext .js,.jsx,.ts,.tsx,.graphql . --fix; prettier --cache --ignore-path .eslintignore --write '**/*.{js,jsx,ts,tsx,graphql,md,json}'",
+    "prettier:check": "prettier --cache --ignore-path .eslintignore --check '**/*.{js,jsx,ts,tsx,graphql,md,json}'"
   },
   "repository": {
     "type": "git",
@@ -47,6 +50,13 @@
   "devDependencies": {
     "@tsconfig/recommended": "^1.0.7",
     "@types/node": "^22.5.4",
+    "@typescript-eslint/eslint-plugin": "^6.8.0",
+    "@typescript-eslint/parser": "^6.8.0",
+    "eslint": "^8.51.0",
+    "eslint-config-prettier": "^9.0.0",
+    "eslint-plugin-import": "^2.28.1",
+    "eslint-plugin-simple-import-sort": "^10.0.0",
+    "eslint_d": "^13.0.0",
     "prettier": "^3.3.3",
     "typescript": "^5.6.2"
   },