refactor(backend): convert all to typescript modules

packages/backend/eslint.config.js

@@ -10,6 +10,11 @@ export default tseslint.config(
   tseslint.configs.recommended,
   nodePlugin.configs['flat/recommended'],
   eslintPlugin.configs['flat/recommended'],
+  {
+    rules: {
+      'n/file-extension-in-import': ['error', 'always'],
+    },
+  },
   {
     languageOptions: {
       globals: {

packages/backend/lib/configs/default.js → packages/backend/lib/configs/default.ts

@@ -1,4 +1,4 @@
-module.exports = {
+const defaultConfig = {
   plugins: ['prettier'],
   extends: ['eslint:recommended'],
   rules: {
@@ -82,3 +82,5 @@ module.exports = {
     },
   ],
 };
+
+export default defaultConfig;

packages/backend/lib/configs/node.js → packages/backend/lib/configs/node.ts

@@ -1,4 +1,4 @@
-module.exports = {
+const nodeConfig = {
   rules: {},
   env: {
     node: true,
@@ -12,3 +12,5 @@ module.exports = {
     ecmaVersion: 2018,
   },
 };
+
+export default nodeConfig;

packages/backend/lib/configs/typescript.js → packages/backend/lib/configs/typescript.ts

@@ -1,4 +1,4 @@
-module.exports = {
+const typescriptConfig = {
   plugins: ['@typescript-eslint'],
   extends: [
     'eslint:recommended',
@@ -20,3 +20,5 @@ module.exports = {
     '@typescript-eslint/no-shadow': 'error',
   },
 };
+
+export default typescriptConfig;

packages/backend/lib/index.ts

@@ -0,0 +1,16 @@
+import defaultConfig from './configs/default.js';
+import nodeConfig from './configs/node.js';
+import typescriptConfig from './configs/typescript.js';
+import arrayForeach from './rules/array-foreach.js';
+import noThen from './rules/no-then.js';
+
+export const rules = {
+  'array-foreach': arrayForeach,
+  'no-then': noThen,
+};
+
+export const configs = {
+  default: defaultConfig,
+  node: nodeConfig,
+  typescript: typescriptConfig,
+};

packages/backend/lib/rules/array-foreach.js → packages/backend/lib/rules/array-foreach.ts

@@ -1,9 +1,12 @@
-module.exports = {
+import { Rule } from 'eslint';
+import docUrl from '../utils/docUrl.js';
+
+const arrayForeach: Rule.RuleModule = {
   meta: {
     type: 'suggestion',
     docs: {
       description: 'enforce `for..of` loops over `Array.forEach`',
-      url: require('../utils/url')(module),
+      url: docUrl(import.meta),
     },
     schema: [],
     messages: {
@@ -13,7 +16,11 @@ module.exports = {
   create(context) {
     return {
       CallExpression(node) {
-        if (node.callee.property && node.callee.property.name === 'forEach') {
+        if (
+          node.callee.type === 'MemberExpression' &&
+          node.callee.property.type === 'Identifier' &&
+          node.callee.property.name === 'forEach'
+        ) {
           context.report({
             node,
             messageId: 'preferMessage',
@@ -23,3 +30,5 @@ module.exports = {
     };
   },
 };
+
+export default arrayForeach;

packages/backend/lib/rules/no-then.js → packages/backend/lib/rules/no-then.ts

@@ -1,9 +1,12 @@
-module.exports = {
+import { Rule } from 'eslint';
+import docUrl from '../utils/docUrl.js';
+
+const noThen: Rule.RuleModule = {
   meta: {
     type: 'suggestion',
     docs: {
       description: 'enforce using `async/await` syntax over Promises',
-      url: require('../utils/url')(module),
+      url: docUrl(import.meta),
     },
     schema: [],
     messages: {
@@ -15,12 +18,12 @@ module.exports = {
   create(context) {
     return {
       MemberExpression(node) {
-        if (node.property && node.property.name === 'then') {
+        if (node.property.type === 'Identifier' && node.property.name === 'then') {
           context.report({
             node: node.property,
             messageId: 'thenMessage',
           });
-        } else if (node.property && node.property.name === 'catch') {
+        } else if (node.property.type === 'Identifier' && node.property.name === 'catch') {
           context.report({
             node: node.property,
             messageId: 'catchMessage',
@@ -30,3 +33,5 @@ module.exports = {
     };
   },
 };
+
+export default noThen;

packages/backend/lib/utils/docUrl.ts

@@ -0,0 +1,13 @@
+import * as path from 'node:path';
+
+import packageJson from '../../package.json' with { type: 'json' };
+
+const docUrl = ({ filename }: ImportMeta) => {
+  const url = new URL(packageJson.homepage);
+  const rule = path.basename(filename, '.js');
+  url.hash = '';
+  url.pathname += `/blob/v${packageJson.version}/docs/rules/${rule}.md`;
+  return url.toString();
+};
+
+export default docUrl;

packages/backend/package.json

@@ -18,7 +18,7 @@
   "main": "lib/index.js",
   "scripts": {
     "lint": "eslint",
-    "test": "mocha tests --recursive",
+    "test": "npm run build && mocha tests --recursive",
     "clean": "rimraf dist",
     "build": "npm run clean && tsc --build"
   },
@@ -41,6 +41,7 @@
     "typescript-eslint": "^8.17.0"
   },
   "devDependencies": {
+    "@types/node": "^22.10.2",
     "eslint-plugin-eslint-plugin": "^6.3.2",
     "eslint-plugin-n": "^17.14.0",
     "mocha": "^11.0.1",

packages/backend/tests/array-foreach.js

@@ -1,30 +1,30 @@
-const rule = require('../lib/rules/array-foreach')
-const RuleTester = require('eslint').RuleTester
+import { RuleTester } from 'eslint';
+import rule from '../dist/lib/rules/array-foreach.js';
 
-const ruleTester = new RuleTester()
+const ruleTester = new RuleTester();
 
 ruleTester.run('array-foreach', rule, {
   valid: [
     {
       code: 'for (const el of els) { el }',
-      parserOptions: {ecmaVersion: 6}
+      languageOptions: { ecmaVersion: 2018 },
     },
     {
       code: 'els.map(el => el)',
-      parserOptions: {ecmaVersion: 6}
+      languageOptions: { ecmaVersion: 2018 },
     },
-    {code: 'forEach()'}
+    { code: 'forEach()' },
   ],
   invalid: [
     {
       code: 'els.forEach(el => el)',
-      parserOptions: {ecmaVersion: 6},
+      languageOptions: { ecmaVersion: 2018 },
       errors: [
         {
           message: 'Prefer for...of instead of Array.forEach',
-          type: 'CallExpression'
-        }
-      ]
-    }
-  ]
-})
+          type: 'CallExpression',
+        },
+      ],
+    },
+  ],
+});

packages/backend/tests/no-then.js

@@ -0,0 +1,39 @@
+import { RuleTester } from 'eslint';
+import rule from '../dist/lib/rules/no-then.js';
+
+const ruleTester = new RuleTester();
+
+ruleTester.run('no-then', rule, {
+  valid: [
+    {
+      code: 'async () => { await promise }',
+      languageOptions: { ecmaVersion: 2018 },
+    },
+    {
+      code: 'async () => { try { await promise } catch (e) { throw e } }',
+      languageOptions: { ecmaVersion: 2018 },
+    },
+  ],
+  invalid: [
+    {
+      code: 'promise.then(() => {})',
+      languageOptions: { ecmaVersion: 2018 },
+      errors: [
+        {
+          message: 'Prefer async/await to Promise.then()',
+          type: 'Identifier',
+        },
+      ],
+    },
+    {
+      code: 'promise.catch(() => {})',
+      languageOptions: { ecmaVersion: 2018 },
+      errors: [
+        {
+          message: 'Prefer async/await to Promise.catch()',
+          type: 'Identifier',
+        },
+      ],
+    },
+  ],
+});

packages/backend/tsconfig.json

@@ -2,12 +2,12 @@
   "$schema": "https://json.schemastore.org/tsconfig",
   "compilerOptions": {
     "lib": ["es2023"],
-    "module": "node16",
+    "module": "nodenext",
     "target": "es2022",
     "strict": true,
     "esModuleInterop": true,
     "skipLibCheck": true,
-    "moduleResolution": "node16",
+    "moduleResolution": "nodenext",
     "allowUnusedLabels": false,
     "allowUnreachableCode": false,
     "exactOptionalPropertyTypes": true,
@@ -22,7 +22,8 @@
     "checkJs": true,
     "outDir": "./dist",
     "sourceMap": true,
-    "baseUrl": "./lib"
+    "baseUrl": "./lib",
+    "resolveJsonModule": true
   },
   "include": ["./lib"]
 }