From 8f6185d077971100a22abbc1c3b0631df9bc1f4c Mon Sep 17 00:00:00 2001
From: Stephen Jason Wang <stephenjasonwang@gmail.com>
Date: Thu, 10 Apr 2025 01:45:45 +0800
Subject: [PATCH 1/2] feat(extensions): add autofix support for consistent file
 extensions in import paths

---
 README.md                |  2 +-
 docs/rules/extensions.md |  2 ++
 src/rules/extensions.js  | 27 ++++++++++++++++++++++++++-
 3 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index 885f34873c..735cf3b689 100644
--- a/README.md
+++ b/README.md
@@ -76,7 +76,7 @@ This plugin intends to support linting of ES2015+ (ES6+) import/export syntax, a
 | [consistent-type-specifier-style](docs/rules/consistent-type-specifier-style.md) | Enforce or ban the use of inline type-only markers for named imports.      |    |       |    | 🔧 |    |    |
 | [dynamic-import-chunkname](docs/rules/dynamic-import-chunkname.md)               | Enforce a leading comment with the webpackChunkName for dynamic imports.   |    |       |    |    | 💡 |    |
 | [exports-last](docs/rules/exports-last.md)                                       | Ensure all exports appear after other statements.                          |    |       |    |    |    |    |
-| [extensions](docs/rules/extensions.md)                                           | Ensure consistent use of file extension within the import path.            |    |       |    |    |    |    |
+| [extensions](docs/rules/extensions.md)                                           | Ensure consistent use of file extension within the import path.            |    |       |    | 🔧 |    |    |
 | [first](docs/rules/first.md)                                                     | Ensure all imports appear before other statements.                         |    |       |    | 🔧 |    |    |
 | [group-exports](docs/rules/group-exports.md)                                     | Prefer named exports to be grouped together in a single export declaration |    |       |    |    |    |    |
 | [imports-first](docs/rules/imports-first.md)                                     | Replaced by `import/first`.                                                |    |       |    | 🔧 |    | ❌  |
diff --git a/docs/rules/extensions.md b/docs/rules/extensions.md
index bd9f3f3584..901d36c0cf 100644
--- a/docs/rules/extensions.md
+++ b/docs/rules/extensions.md
@@ -1,5 +1,7 @@
 # import/extensions
 
+🔧 This rule is automatically fixable by the [`--fix` CLI option](https://eslint.org/docs/latest/user-guide/command-line-interface#--fix).
+
 <!-- end auto-generated rule header -->
 
 Some file resolve algorithms allow you to omit the file extension within the import source path. For example the `node` resolver (which does not yet support ESM/`import`) can resolve `./foo/bar` to the absolute path `/User/someone/foo/bar.js` because the `.js` extension is resolved automatically by default in CJS. Depending on the resolver you can configure more extensions to get resolved automatically.
diff --git a/src/rules/extensions.js b/src/rules/extensions.js
index 2aeef64758..9c03d229bb 100644
--- a/src/rules/extensions.js
+++ b/src/rules/extensions.js
@@ -46,6 +46,7 @@ function buildProperties(context) {
     defaultConfig: 'never',
     pattern: {},
     ignorePackages: false,
+    fix: false,
   };
 
   context.options.forEach((obj) => {
@@ -72,6 +73,11 @@ function buildProperties(context) {
       result.ignorePackages = obj.ignorePackages;
     }
 
+    // If fix is provided, transfer it to result
+    if (obj.fix !== undefined) {
+      result.fix = obj.fix;
+    }
+
     if (obj.checkTypeImports !== undefined) {
       result.checkTypeImports = obj.checkTypeImports;
     }
@@ -97,7 +103,7 @@ module.exports = {
       description: 'Ensure consistent use of file extension within the import path.',
       url: docsUrl('extensions'),
     },
-
+    fixable: 'code',
     schema: {
       anyOf: [
         {
@@ -225,6 +231,14 @@ module.exports = {
             node: source,
             message:
               `Missing file extension ${extension ? `"${extension}" ` : ''}for "${importPathWithQueryString}"`,
+            ...props.fix && extension ? {
+              fix(fixer) {
+                return fixer.replaceText(
+                  source,
+                  JSON.stringify(`${importPathWithQueryString}.${extension}`),
+                );
+              },
+            } : {},
           });
         }
       } else if (extension) {
@@ -232,6 +246,17 @@ module.exports = {
           context.report({
             node: source,
             message: `Unexpected use of file extension "${extension}" for "${importPathWithQueryString}"`,
+            ...props.fix
+              ? {
+                fix(fixer) {
+                  return fixer.replaceText(
+                    source,
+                    JSON.stringify(
+                      importPath.slice(0, -(extension.length + 1)),
+                    ),
+                  );
+                },
+              } : {},
           });
         }
       }

From b8e73709316cd6caf8f40444abc537606c5b2e17 Mon Sep 17 00:00:00 2001
From: Stephen Jason Wang <stephenjasonwang@gmail.com>
Date: Thu, 10 Apr 2025 23:42:04 +0800
Subject: [PATCH 2/2] test: add test cases for extensions rule with fix option

---
 tests/src/rules/extensions.js | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/tests/src/rules/extensions.js b/tests/src/rules/extensions.js
index 8843713e34..0ac1a59688 100644
--- a/tests/src/rules/extensions.js
+++ b/tests/src/rules/extensions.js
@@ -155,6 +155,16 @@ ruleTester.run('extensions', rule, {
       ].join('\n'),
       options: ['always'],
     }),
+
+    test({
+      code: "import foo from './foo';",
+      options: [{ fix: true }],
+    }),
+
+    test({
+      code: "import foo from './foo.js';",
+      options: [{ fix: true, pattern: { js: 'always' } }],
+    }),
   ],
 
   invalid: [
@@ -652,6 +662,13 @@ ruleTester.run('extensions', rule, {
         },
       ],
     }),
+
+    test({
+      code: 'import foo from "./foo.js";',
+      options: ['always', { pattern: { js: 'never' }, fix: true }],
+      errors: [{ message: 'Unexpected use of file extension "js" for "./foo.js"' }],
+      output: 'import foo from "./foo";',
+    }),
   ],
 });