Support for ESLint Flat Config (#15)

* - Support for ESLint Flat Config

* Change files

* - Updating just-scripts version

* - Converting to Flat Config

* Change files

* Change files

* - Fixing legacy file name

change/@minecraft-core-build-tasks-da7d6e11-184c-4135-b8bc-a3626a674a63.json

@@ -0,0 +1,7 @@
+{
+  "type": "patch",
+  "comment": "Support for ESLint Flat Config",
+  "packageName": "@minecraft/core-build-tasks",
+  "email": "frgarc@microsoft.com",
+  "dependentChangeType": "patch"
+}

change/@minecraft-math-53db88ef-0630-4f25-900a-cab0514b466e.json

@@ -0,0 +1,7 @@
+{
+  "type": "patch",
+  "comment": "Using flat config",
+  "packageName": "@minecraft/math",
+  "email": "frgarc@microsoft.com",
+  "dependentChangeType": "patch"
+}

change/eslint-plugin-minecraft-linting-7b130e35-6c54-4c46-bf1e-4398f642ef8a.json

@@ -0,0 +1,7 @@
+{
+  "type": "patch",
+  "comment": "Support for ESLint Flat Config",
+  "packageName": "eslint-plugin-minecraft-linting",
+  "email": "frgarc@microsoft.com",
+  "dependentChangeType": "patch"
+}

libraries/math/eslint.config.mjs

@@ -0,0 +1,3 @@
+import configMinecraftScripting from 'eslint-config-minecraft-scripting';
+
+export default [...configMinecraftScripting];

tools/core-build-tasks/package.json

@@ -18,6 +18,7 @@
     "@microsoft/api-extractor": "^7.38.3",
     "esbuild": "^0.20.1",
     "dotenv": "^16.0.2",
+    "just-scripts": "^2.2.1",
     "prettier": "^2.8.2",
     "rimraf": "^3.0.2",
     "vitest": "^0.34.6",
@@ -27,9 +28,8 @@
   "devDependencies": {
     "@types/node": "^14.0.0 || ^16.0.0 || ^18.0.0",
     "@types/rimraf": "^3.0.2",
-    "just-scripts": "^2.1.3",
     "ts-node": "^10.9.1",
     "tsconfig": "*",
     "typescript": "^5.2.2"
   }
-}
+}

tools/core-build-tasks/src/tasks/coreLint.ts

@@ -1,21 +1,61 @@
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT License.
 
+import { execSync } from 'child_process';
 import { existsSync } from 'fs';
-import type { TaskFunction } from 'just-scripts';
-import { condition, eslintTask, prettierCheckTask, prettierTask, series, task } from 'just-scripts';
+import { TaskFunction, condition, logger, prettierCheckTask, prettierTask, series, task } from 'just-scripts';
 import path from 'path';
 import process from 'process';
 
+const LEGACY_CONFIG_FILES = ['.eslintrc.js'];
+const FLAT_CONFIG_FILES = ['eslint.config.js', 'eslint.config.mjs', 'eslint.config.cjs'];
+const POSSIBLE_CONFIG_FILES = [...LEGACY_CONFIG_FILES, ...FLAT_CONFIG_FILES];
+
+function getConfigFilePath(): string | undefined {
+    for (const file of POSSIBLE_CONFIG_FILES) {
+        const configPath = path.resolve(process.cwd(), file);
+        if (existsSync(configPath)) {
+            return configPath;
+        }
+    }
+
+    return undefined;
+}
+
+function eslintTask(files: string[], fix?: boolean): TaskFunction {
+    return () => {
+        const configFilePath = getConfigFilePath();
+        if (configFilePath) {
+            // Setting ESLINT_USE_FLAT_CONFIG environment variable to indicate if the config file is flat or not.
+            // ESLint is not able to determine the type in all the cases, so we need to help it.
+            process.env['ESLINT_USE_FLAT_CONFIG'] = FLAT_CONFIG_FILES.some(file => configFilePath.endsWith(file))
+                ? 'true'
+                : 'false';
+            const cmd = ['eslint', ...files, '--config', configFilePath, ...(fix ? ['--fix'] : []), '--color'].join(
+                ' '
+            );
+            logger.info(`Running command: ${cmd}`);
+            return execSync(cmd, { stdio: 'inherit' });
+        }
+
+        // no-op if the config file does not exist.
+        return Promise.resolve();
+    };
+}
+
 export function coreLint(files: string[], fix?: boolean): TaskFunction {
     task('verify-lint', () => {
-        // If the process working directory does not have an `.eslintrc.js` file, fail the build
-        const lintConfig = path.resolve(process.cwd(), '.eslintrc.js');
-        if (!existsSync(lintConfig)) {
-            throw new Error(`.eslintrc.js not found at ${lintConfig}.`);
+        // If the process working directory does not have an eslint configuration file, fail the build:
+        // https://eslint.org/docs/latest/use/configure/configuration-files-new
+        if (!getConfigFilePath()) {
+            throw new Error(
+                `ESLint config file not found at ${process.cwd()}. Possible values: [${POSSIBLE_CONFIG_FILES.join(
+                    ', '
+                )}]`
+            );
         }
     });
-    task('eslint', eslintTask({ files, fix }));
+    task('eslint', eslintTask(files, fix));
     task('prettier-fix', prettierTask({ files }));
     task('prettier-check', prettierCheckTask({ files }));
 

tools/eslint-config-minecraft-scripting/index.mjs

@@ -0,0 +1,63 @@
+import eslintConfigPrettier from 'eslint-config-prettier';
+import eslintPluginUnicorn from 'eslint-plugin-unicorn';
+import eslint from '@eslint/js';
+import globals from 'globals';
+import header from 'eslint-plugin-header';
+import minecraftLinting from 'eslint-plugin-minecraft-linting';
+import tsEslint from '@typescript-eslint/eslint-plugin';
+import tsParser from '@typescript-eslint/parser';
+
+export default [
+    eslintConfigPrettier,
+    eslint.configs.recommended,
+    {
+        files: ['**/*.{ts,tsx,js,jsx}', '*.ts'],
+        languageOptions: {
+            parser: tsParser,
+            parserOptions: {
+                ecmaVersion: 'latest',
+                project: './tsconfig.json',
+            },
+            globals: {
+                ...globals.node,
+            },
+        },
+        plugins: {
+            header,
+            tsEslint,
+            '@typescript-eslint': tsEslint,
+            unicorn: eslintPluginUnicorn,
+            'minecraft-linting': minecraftLinting,
+        },
+        rules: {
+            ...tsEslint.configs['eslint-recommended'].rules,
+            ...tsEslint.configs['recommended'].rules,
+            'unicorn/no-abusive-eslint-disable': 'error',
+            'unicorn/no-null': ['error', { checkStrictEquality: true }],
+            '@typescript-eslint/no-empty-function': 'off',
+            'no-unused-vars': 'off',
+            '@typescript-eslint/no-explicit-any': 'error',
+            '@typescript-eslint/no-floating-promises': ['error', { ignoreVoid: true }],
+            '@typescript-eslint/no-unused-vars': [
+                'error',
+                {
+                    argsIgnorePattern: '^_',
+                    varsIgnorePattern: '^_',
+                    caughtErrorsIgnorePattern: '^_',
+                },
+            ],
+            '@typescript-eslint/restrict-template-expressions': ['error', { allowNumber: true, allowBoolean: true }],
+            eqeqeq: ['error', 'always'],
+            '@typescript-eslint/no-unsafe-assignment': 'error',
+            '@typescript-eslint/no-unsafe-member-access': 'error',
+            '@typescript-eslint/no-unsafe-call': 'error',
+            'header/header': [
+                2,
+                'line',
+                [' Copyright (c) Microsoft Corporation.', ` Licensed under the MIT License.`],
+                1,
+            ],
+            'minecraft-linting/avoid-unnecessary-command': 'error',
+        },
+    },
+];

tools/eslint-config-minecraft-scripting/package.json

@@ -1,7 +1,7 @@
 {
     "name": "eslint-config-minecraft-scripting",
     "version": "0.0.1",
-    "main": "index.js",
+    "main": "index.mjs",
     "license": "MIT",
     "private": true,
     "dependencies": {

tools/eslint-plugin-minecraft-linting/eslint.config.mjs

@@ -0,0 +1,3 @@
+import configMinecraftScripting from 'eslint-config-minecraft-scripting';
+
+export default [...configMinecraftScripting];

tools/eslint-plugin-minecraft-linting/package.json

@@ -25,10 +25,10 @@
     "eslint-plugin-header": "^3.1.1",
     "eslint-config-prettier": "^9.0.0",
     "eslint-plugin-unicorn": "^42.0.0",
-    "just-scripts": "^2.1.3",
+    "just-scripts": "^2.2.1",
     "tsconfig": "*"
   },
   "publishConfig": {
     "access": "public"
   }
-}
+}

tools/eslint-plugin-minecraft-linting/src/index.ts

@@ -3,7 +3,14 @@
 
 import AvoidUnnecessaryCommand from './Rules/AvoidUnnecessaryCommand';
 
+// eslint-disable-next-line @typescript-eslint/no-unsafe-assignment, @typescript-eslint/no-var-requires
+const { name, version }: { name: string; version: string } = require('../package.json');
+
 module.exports = {
+    meta: {
+        name,
+        version,
+    },
     rules: {
         'avoid-unnecessary-command': AvoidUnnecessaryCommand,
     },