[New] jsx-filename-extension: add ignoreFilesWithoutCode option to allow empty files

Author: burtek

Diff for: CHANGELOG.md

@@ -13,6 +13,7 @@ This change log adheres to standards from [Keep a CHANGELOG](https://keepachange
 * [`prefer-read-only-props`], [`prop-types`], component detection: allow components to be async functions ([#3654][] @pnodet)
 * [`no-unknown-property`]: support `onResize` on audio/video tags ([#3662][] @caesar1030)
 * [`jsx-wrap-multilines`]: add `never` option to prohibit wrapping parens on multiline JSX ([#3668][] @reedws)
+* [`jsx-filename-extension`]: add `ignoreFilesWithoutCode` option to allow empty files ([#3674][] @burtek)
 
 ### Fixed
 * [`jsx-no-leaked-render`]: preserve RHS parens for multiline jsx elements while fixing ([#3623][] @akulsr0)
@@ -27,6 +28,7 @@ This change log adheres to standards from [Keep a CHANGELOG](https://keepachange
 * [Refactor] [`jsx-props-no-multi-spaces`]: extract type parameters to var ([#3634][] @HenryBrown0)
 * [Docs] [`jsx-key`]: fix correct example ([#3656][] @developer-bandi)
 
+[#3674]: https://github.com/jsx-eslint/eslint-plugin-react/pull/3674
 [#3668]: https://github.com/jsx-eslint/eslint-plugin-react/pull/3668
 [#3666]: https://github.com/jsx-eslint/eslint-plugin-react/pull/3666
 [#3662]: https://github.com/jsx-eslint/eslint-plugin-react/pull/3662

Diff for: docs/rules/jsx-filename-extension.md

@@ -46,6 +46,16 @@ The set of allowed extensions is configurable. By default '.jsx' is allowed. If
 }
 ```
 
+### `ignoreFilesWithoutCode` (default: `false`)
+
+If enabled, files that do not contain code (i.e. are empty, contain only whitespaces or comments) will not be rejected.
+
+```js
+"rules": {
+  "react/jsx-filename-extension": [1, { "ignoreFilesWithoutCode": true }]
+}
+```
+
 ## When Not To Use It
 
 If you don't care about restricting the file extensions that may contain JSX.

Diff for: lib/rules/jsx-filename-extension.js

@@ -16,6 +16,7 @@ const report = require('../util/report');
 const DEFAULTS = {
   allow: 'always',
   extensions: ['.jsx'],
+  ignoreFilesWithoutCode: false,
 };
 
 // ------------------------------------------------------------------------------
@@ -50,6 +51,9 @@ module.exports = {
             type: 'string',
           },
         },
+        ignoreFilesWithoutCode: {
+          type: 'boolean',
+        },
       },
       additionalProperties: false,
     }],
@@ -67,6 +71,8 @@ module.exports = {
 
     const allow = (context.options[0] && context.options[0].allow) || DEFAULTS.allow;
     const allowedExtensions = (context.options[0] && context.options[0].extensions) || DEFAULTS.extensions;
+    const ignoreFilesWithoutCode = (context.options[0] && context.options[0].ignoreFilesWithoutCode)
+      || DEFAULTS.ignoreFilesWithoutCode;
     const isAllowedExtension = allowedExtensions.some((extension) => filename.slice(-extension.length) === extension);
 
     function handleJSX(node) {
@@ -97,6 +103,9 @@ module.exports = {
         }
 
         if (isAllowedExtension && allow === 'as-needed') {
+          if (ignoreFilesWithoutCode && node.body.length === 0) {
+            return;
+          }
           report(context, messages.extensionOnlyForJSX, 'extensionOnlyForJSX', {
             node,
             data: {

Diff for: tests/lib/rules/jsx-filename-extension.js

@@ -29,6 +29,13 @@ const parserOptions = {
 const withJSXElement = 'module.exports = function MyComponent() { return <div>\n<div />\n</div>; }';
 const withJSXFragment = 'module.exports = function MyComponent() { return <>\n</>; }';
 const withoutJSX = 'module.exports = {}';
+const onlyComments = [
+  '// some initial comment',
+  '',
+  '/* multiline',
+  ' * comment',
+  ' */',
+].join('\n');
 
 // ------------------------------------------------------------------------------
 // Tests
@@ -80,6 +87,21 @@ ruleTester.run('jsx-filename-extension', rule, {
       code: withJSXFragment,
       features: ['fragment'],
     },
+    {
+      filename: 'MyComponent.js',
+      code: onlyComments,
+      options: [{ allow: 'as-needed' }],
+    },
+    {
+      filename: 'MyComponent.jsx',
+      code: onlyComments,
+      options: [{ allow: 'as-needed', ignoreFilesWithoutCode: true }],
+    },
+    {
+      filename: 'MyComponent.jsx',
+      code: '',
+      options: [{ allow: 'as-needed', ignoreFilesWithoutCode: true }],
+    },
   ]),
 
   invalid: parsers.all([