feat!: Migrate to ESLint v9.

jest.js → JestConfig.mjs

@@ -1,9 +1,15 @@
-module.exports = {
-    env: {
-        jest: true,
+import globals from "globals";
+
+
+const JestConfig = {
+    languageOptions: {
+        globals: {
+            ...globals.jest,
+        },
     },
     rules: {
         "no-magic-numbers": "off",
+
         "jsdoc/check-tag-names": [
             "warn",
             {
@@ -12,3 +18,6 @@ module.exports = {
         ],
     },
 };
+
+
+export default JestConfig;

MeteorConfig.mjs

@@ -0,0 +1,23 @@
+import globals from "globals";
+
+
+const MeteorConfig = {
+    languageOptions: {
+        globals: {
+            ...globals.jest,
+            ...globals.meteor,
+            ...globals.node,
+        },
+    },
+    settings: {
+        "import/core-modules": [
+            "meteor/meteor",
+            "meteor/mongo",
+            "meteor/accounts-base",
+            "meteor/react-meteor-data",
+        ],
+    },
+};
+
+
+export default MeteorConfig;

README.md

@@ -1,6 +1,8 @@
 # eslint-config-yscope
 
-This repository contains ESLint configurations for various JavaScript environments under the `yscope` namespace. Our configurations are designed to enforce a consistent coding style and catch common bugs, making your codebase more maintainable and error-free.
+This repository contains ESLint ["flat"][eslint-flat-config] configurations for various JavaScript
+environments under the `yscope` namespace. Our configurations are designed to enforce a consistent
+coding style and catch common bugs, making your codebase more maintainable and error-free.
 
 ## Installation
 
@@ -14,83 +16,175 @@ yarn add --dev eslint-config-yscope
 
 ### For Older Node.js Versions
 
-If you are using `npm` version >= 3 or < 7, you need to install the `peerDependencies` specified in https://github.com/y-scope/eslint-config-yscope/blob/e0dc97bd6f738b06ee692bd52f0fceb6996c1625/package.json#L14-L26
-
-Alternatively, you can upgrade your `npm` to the latest version compatible with your Node.js version.
-- Node.js verions below v16: `npm i -g npm@9`
-- Node.js v16 or above: `npm i -g npm@latest`
+This package requires ESLint 9, which in turn requires Node.js 18 or above. If you are using an
+older version of Node.js, you can use version `0.0.32` of this package, which is compatible with
+ESLint 8. Detailed setup instructions for this version are available in the 
+[older version's README][readme-0.0.32].
 
 ## Usage
 
-After installation, you can use one of the configurations by adding it to the `extends` section in your `.eslintrc` (or `.eslintrc.js`, `.eslintrc.json`, etc.) file, or in an attribute named `eslintConfig` in your `package.json` file.
-
-### ESLint config example
-
-```json
-{
-  "extends": ["yscope/common"]
-}
-```
+After installation, you can create an `eslint.config.mjs` configuration file in the root directory
+of your project and export an array of configuration objects.
 
 ### Available Configurations
 
-The available configs are:
-
-- `yscope/common`: A general ESLint configuration suitable for a wide range of JavaScript projects.
-- `yscope/react`: Tailored ESLint configuration for React applications.
-- `yscope/meteor`: A specialized ESLint configuration for Meteor projects.
-- `yscope/typescipt`: Designed specifically for TypeScript applications.
-- `yscope/jest`: A Jest-specific ESLint configuration intended to override other configurations for Jest test files.
-
-### Jest-Specific Configuration
-
-The Jest configuration is **not standalone** and should be used alongside other configurations. It is intended to
-override rules for Jest test files, so it should appear *last* in your `overrides` array.
-
-#### Example Usage
-
-If your project uses Jest, you can add an override for your test files as follows:
-
-```json5
-{
-  "overrides": [
-    // ...
-    {
-      "files": ["test/**/*"],
-      "extends": ["yscope/jest"]
-    }
-  ]
-}
-```
-
-### For TypeScript Configuration
-
-TypeScript-related dependencies are not automatically installed because not every configuration requires them.
-Before you can use this configuration, you need to install the dependencies manually.
-
-```shell
-npm install --save-dev eslint-import-resolver-typescript @typescript-eslint/parser @typescript-eslint/eslint-plugin
-```
-
-Then in your ESLint configuration:
-
-```json
-{
-  "extends": [
-    "yscope/common",
-    "yscope/typescript"
-  ]
-}
-```
+Some configurations are provided as standalone configuration objects, which can be directly
+referenced once imported:
+- `CommonConfig`: A general ESLint configuration suitable for a wide range of JavaScript projects.
+- `JestConfig`: A specialized ESLint configuration for Jest files.
+- `MeteorConfig`: A specialized ESLint configuration for Meteor projects.
+
+The other configurations are provided as a group of configuration objects stored in an array. To use
+these configurations, you need to utilize the "spread" (`...`) syntax to unpack the configuration
+objects into your own configuration array:
+- `StylisticConfigArray`: A configuration for stylistic formatting. It is typically combined with
+  `CommonConfig`, as shown in the [ESLint config examples](#eslint-config-examples).
+- `ReactConfigArray`: A specialized ESLint configuration for React applications.
+- `TsConfigArray`: A specialized ESLint configuration for TypeScript projects. A helper
+  `createTsConfigOverride` is also provided. See [ESLint config examples](#eslint-config-examples) for
+  details on how to set it up.
+
+
+### ESLint config examples
+
+1. For use with a CommonJS Node.js project:
+    ```javascript
+    import globals from "globals";
+
+    import CommonConfig from "eslint-config-yscope/CommonConfig.mjs";
+    import StylisticConfigArray from "eslint-config-yscope/StylisticConfigArray.mjs";
+
+
+    const EslintConfig = [
+        CommonConfig,
+        ...StylisticConfigArray,
+        {
+            languageOptions: {
+                globals: {
+                    ...globals.node,
+                },
+            },
+        },
+        {
+            rules: {
+                // Your own overrides
+            },
+        },
+    ];
+
+
+    export default EslintConfig;
+    ```
+
+2. For use with a JavaScript React.js project:
+    ```javascript
+    import CommonConfig from "eslint-config-yscope/CommonConfig.mjs";
+    import ReactConfigArray from "eslint-config-yscope/ReactConfigArray.mjs";
+    import StylisticConfigArray from "eslint-config-yscope/StylisticConfigArray.mjs";
+
+
+    const EslintConfig = [
+        CommonConfig,
+        ...StylisticConfigArray,
+        ...ReactConfigArray,
+    ];
+
+
+    export default EslintConfig;
+    ```
+
+3. For use with a TypeScript React.js project:
+    ```javascript
+    import CommonConfig from "eslint-config-yscope/CommonConfig.mjs";
+    import ReactConfigArray from "eslint-config-yscope/ReactConfigArray.mjs";
+    import StylisticConfigArray from "eslint-config-yscope/StylisticConfigArray.mjs";
+    import TsConfigArray from "eslint-config-yscope/TsConfigArray.mjs";
+
+
+    const EslintConfig = [
+        CommonConfig,
+
+        // NOTE: The map below must be placed directly before the spread `StylisticConfigArray`.
+        ...TsConfigArray.map(
+            (config) => ({
+                files: [
+                    "**/*.ts",
+                    "**/*.tsx",
+                ],
+                ...config,
+            })
+        ),
+        ...StylisticConfigArray,
+
+        ...ReactConfigArray,
+    ];
+
+
+    export default EslintConfig;
+    ```
+
+4. For use with a TypeScript project with multiple `tsconfig.json` files: In projects that include
+   multiple `tsconfig.json` files for different source types, such as a Vite project created from
+   the `react-ts` template, you can use the helper function `createTsConfigOverride` to generate
+   configuration overrides. This ensures proper handling of imports and resolution.
+   ```javascript
+   import CommonConfig from "eslint-config-yscope/CommonConfig.mjs";
+   import ReactConfigArray from "eslint-config-yscope/ReactConfigArray.mjs";
+   import StylisticConfigArray from "eslint-config-yscope/StylisticConfigArray.mjs";
+   import TsConfigArray, {createTsConfigOverride} from "eslint-config-yscope/TsConfigArray.mjs";
+
+
+   const EslintConfig = [
+       {
+           ignores: [
+               "dist/",
+               "node_modules/",
+           ],
+       },
+       CommonConfig,
+       ...TsConfigArray.map(
+           (config) => ({
+               files: [
+                   "**/*.ts",
+                   "**/*.tsx",
+               ],
+               ...config,
+           })
+       ),
+       createTsConfigOverride(
+           [
+               "src/**/*.ts",
+               "src/**/*.tsx",
+           ],
+           "tsconfig.app.json"
+       ),
+       createTsConfigOverride(
+           ["vite.config.ts"],
+           "tsconfig.node.json"
+       ),
+       ...StylisticConfigArray,
+       ...ReactConfigArray,
+   ];
+
+
+   export default EslintConfig;
+   ```
 
 ## Customization
 
-Each configuration can be further customized and extended as per your project's needs. You can override specific rules by adding them to your ESLint configuration file.
+Each configuration can be further customized and extended as per your project's needs. You can
+override specific rules by adding them to your ESLint configuration file.
 
 ## Contributing
 
-We welcome contributions to the `eslint-config-yscope`! If you have suggestions or improvements, feel free to open an issue or a pull request.
+We welcome contributions to the `eslint-config-yscope`! If you have suggestions or improvements,
+feel free to open an issue or a pull request.
 
 ## License
 
-This project is licensed under Apache License 2.0. Please see the [LICENSE](https://github.com/y-scope/eslint-config-yscope/blob/main/LICENSE) file for more details.
+This project is licensed under Apache License 2.0. Please see the [LICENSE][license] file for more
+details.
+
+[eslint-flat-config]: https://eslint.org/docs/v9.x/use/configure/migration-guide
+[license]: https://github.com/y-scope/eslint-config-yscope/blob/main/LICENSE
+[readme-0.0.32]: https://github.com/y-scope/eslint-config-yscope/blob/f75571723ff1a6fd734ab82b4a399c2c1c92c5fb/README.md#for-older-nodejs-versions