Merge pull request #23 from gajus/gajus/add-require-extension

feat: add require-extension rule

.README/rules/require-extension.md

@@ -0,0 +1,54 @@
+### `require-extension`
+
+Adds `.js` extension to all imports and exports.
+
+It resolves the following cases:
+
+#### Relative imports
+
+Relative imports that resolve to a file of the same name:
+
+```js
+import './foo'; // => import './foo.js';
+```
+
+Relative imports that resolve to an index file:
+
+```js
+import './foo'; // => import './foo/index.js';
+```
+
+The above examples would also work if the file extension was `.ts` or `.tsx`, i.e.
+
+```js
+import './foo'; // => import './foo.ts';
+import './foo'; // => import './foo/index.tsx';
+```
+
+#### TypeScript paths
+
+For this to work, you have to [configure `import/resolver`](https://www.npmjs.com/package/eslint-import-resolver-typescript):
+
+```ts
+settings: {
+  'import/resolver': {
+    typescript: {
+      project: path.resolve(__dirname, 'tsconfig.json'),
+    },
+  },
+},
+```
+
+Imports that resolve to a file of the same name:
+
+```js
+import { foo } from '@/foo'; // => import { foo } from '@/foo.js';
+```
+
+Imports that resolve to an index file:
+
+```js
+import { foo } from '@/foo'; // => import { foo } from '@/foo/index.js';
+```
+
+<!-- assertions requireExtension -->

.gitignore

@@ -1,6 +1,7 @@
 /coverage
 /dist
 /node_modules
+/pnpm-lock.yaml
 *.log
 .*
 !.eslintignore
@@ -10,4 +11,4 @@
 !.gitignore
 !.husky
 !.README
-!.releaserc
+!.releaserc

src/configs/recommended.json

@@ -31,6 +31,7 @@
     "canonical/import-specifier-newline": 1,
     "canonical/no-restricted-strings": 0,
     "canonical/no-use-extend-native": 2,
+    "canonical/require-extension": 0,
     "canonical/sort-keys": [
       2,
       "asc",

src/index.ts

@@ -12,6 +12,7 @@ import noUseExtendNative from './rules/noUseExtendNative';
 import preferImportAlias from './rules/preferImportAlias';
 import preferInlineTypeImport from './rules/preferInlineTypeImport';
 import preferUseMount from './rules/preferUseMount';
+import requireExtension from './rules/requireExtension';
 import sortKeys from './rules/sortKeys';
 import virtualModule from './rules/virtualModule';
 
@@ -33,6 +34,7 @@ export = {
     'prefer-import-alias': preferImportAlias,
     'prefer-inline-type-import': preferInlineTypeImport,
     'prefer-use-mount': preferUseMount,
+    'require-extension': requireExtension,
     'sort-keys': sortKeys,
     'virtual-module': virtualModule,
   },
@@ -48,6 +50,7 @@ export = {
     'no-use-extend-native': 0,
     'prefer-inline-type-import': 0,
     'prefer-use-mount': 0,
+    'require-extension': 0,
     'sort-keys': 0,
   },
 };

src/rules/requireExtension.ts

@@ -0,0 +1,201 @@
+import { existsSync, lstatSync, readFileSync } from 'node:fs';
+import { dirname, resolve } from 'node:path';
+import { type TSESTree } from '@typescript-eslint/utils';
+import { type RuleFixer } from '@typescript-eslint/utils/dist/ts-eslint';
+import resolveImport from 'eslint-module-utils/resolve';
+import { createRule } from '../utilities';
+
+const extensions = ['.js', '.ts', '.tsx'];
+
+type Options = [];
+
+type MessageIds = 'extensionMissing';
+
+const isExistingFile = (fileName: string) => {
+  return existsSync(fileName) && lstatSync(fileName).isFile();
+};
+
+const fixRelativeImport = (
+  fixer: RuleFixer,
+  node: TSESTree.ImportDeclaration,
+  fileName: string,
+  overrideExtension: boolean = true,
+) => {
+  const importPath = resolve(dirname(fileName), node.source.value);
+
+  for (const extension of extensions) {
+    if (isExistingFile(importPath + extension)) {
+      return fixer.replaceTextRange(
+        node.source.range,
+        `'${node.source.value + (overrideExtension ? '.js' : extension)}'`,
+      );
+    }
+  }
+
+  for (const extension of extensions) {
+    if (isExistingFile(resolve(importPath, 'index') + extension)) {
+      return fixer.replaceTextRange(
+        node.source.range,
+        `'${
+          node.source.value + '/index' + (overrideExtension ? '.js' : extension)
+        }'`,
+      );
+    }
+  }
+
+  return null;
+};
+
+const fixPathImport = (
+  fixer: RuleFixer,
+  node: TSESTree.ImportDeclaration,
+  fileName: string,
+  aliasPath: string,
+  resolvedImportPath: string,
+  overrideExtension: boolean = true,
+) => {
+  const importPath = node.source.value.replace(aliasPath, '');
+
+  for (const extension of extensions) {
+    if (resolvedImportPath.endsWith(importPath + extension)) {
+      return fixer.replaceTextRange(
+        node.source.range,
+        `'${node.source.value + (overrideExtension ? '.js' : extension)}'`,
+      );
+    }
+  }
+
+  for (const extension of extensions) {
+    if (resolvedImportPath.endsWith(importPath + '/index' + extension)) {
+      return fixer.replaceTextRange(
+        node.source.range,
+        `'${
+          node.source.value + '/index' + (overrideExtension ? '.js' : extension)
+        }'`,
+      );
+    }
+  }
+
+  return null;
+};
+
+type AliasPaths = {
+  [key: string]: string[];
+};
+
+type TSConfig = {
+  compilerOptions: {
+    paths?: AliasPaths;
+  };
+};
+
+const findAliasPath = (aliasPaths: AliasPaths, importPath: string) => {
+  return Object.keys(aliasPaths).find((path) => {
+    if (!path.endsWith('*')) {
+      return false;
+    }
+
+    const pathWithoutWildcard = path.slice(0, -1);
+
+    return importPath.startsWith(pathWithoutWildcard);
+  });
+};
+
+const endsWith = (subject: string, needles: string[]) => {
+  return needles.some((needle) => {
+    return subject.endsWith(needle);
+  });
+};
+
+export default createRule<Options, MessageIds>({
+  create: (context) => {
+    return {
+      ImportDeclaration: (node) => {
+        const importPath = node.source.value;
+
+        const importPathHasExtension = endsWith(importPath, extensions);
+
+        if (importPathHasExtension) {
+          return;
+        }
+
+        if (importPath.startsWith('.')) {
+          context.report({
+            fix(fixer) {
+              return fixRelativeImport(fixer, node, context.getFilename());
+            },
+            messageId: 'extensionMissing',
+            node,
+          });
+
+          return;
+        }
+
+        // @ts-expect-error we know this setting exists
+        const project = (context.settings['import/resolver']?.typescript
+          ?.project ?? null) as string | null;
+
+        if (typeof project !== 'string') {
+          return;
+        }
+
+        const tsconfig: TSConfig = JSON.parse(readFileSync(project, 'utf8'));
+
+        const paths = tsconfig?.compilerOptions?.paths;
+
+        if (!paths) {
+          return;
+        }
+
+        const aliasPath = findAliasPath(paths, importPath);
+
+        if (!aliasPath) {
+          return;
+        }
+
+        const aliasPathWithoutWildcard = aliasPath.slice(0, -1);
+
+        if (!aliasPathWithoutWildcard) {
+          throw new Error('Path without wildcard is empty');
+        }
+
+        const resolvedImportPath: string | null = resolveImport(
+          importPath,
+          context,
+        );
+
+        if (!resolvedImportPath) {
+          return;
+        }
+
+        context.report({
+          fix(fixer) {
+            return fixPathImport(
+              fixer,
+              node,
+              context.getFilename(),
+              aliasPathWithoutWildcard,
+              resolvedImportPath,
+            );
+          },
+          messageId: 'extensionMissing',
+          node,
+        });
+      },
+    };
+  },
+  defaultOptions: [],
+  meta: {
+    docs: {
+      description: '',
+      recommended: 'error',
+    },
+    fixable: 'code',
+    messages: {
+      extensionMissing: 'Must include file extension "{{extension}}"',
+    },
+    schema: [],
+    type: 'layout',
+  },
+  name: 'require-extension',
+});

tests/fixtures/.eslintrc

@@ -0,0 +1,7 @@
+{
+  "rules": {
+    "@typescript-eslint/no-unused-vars": 0,
+    "import/extensions": 0,
+    "no-console": 0
+  }
+}

tests/fixtures/requireExtension/pathsImport/foo.ts

@@ -0,0 +1 @@
+export const foo = 'FOO';

tests/fixtures/requireExtension/pathsImport/subject-fixed.ts

@@ -0,0 +1 @@
+import { foo } from '@/foo.js';

tests/fixtures/requireExtension/pathsImport/subject.ts

@@ -0,0 +1 @@
+import { foo } from '@/foo';

tests/fixtures/requireExtension/pathsImport/tsconfig.json

@@ -0,0 +1,13 @@
+{
+  "compilerOptions": {
+    "baseUrl": ".",
+    "paths": {
+      "@/*": [
+        "*"
+      ]
+    }
+  },
+  "include": [
+    "."
+  ]
+}

tests/fixtures/requireExtension/pathsImportWithExtension/foo.ts

@@ -0,0 +1 @@
+export const foo = 'FOO';

tests/fixtures/requireExtension/pathsImportWithExtension/subject.ts

@@ -0,0 +1 @@
+import { foo } from '@/foo.js';

tests/fixtures/requireExtension/pathsImportWithExtension/tsconfig.json

@@ -0,0 +1,13 @@
+{
+  "compilerOptions": {
+    "baseUrl": ".",
+    "paths": {
+      "@/*": [
+        "*"
+      ]
+    }
+  },
+  "include": [
+    "."
+  ]
+}

tests/fixtures/requireExtension/pathsImportWithIndex/foo/index.ts

@@ -0,0 +1 @@
+export const foo = 'FOO';

tests/fixtures/requireExtension/pathsImportWithIndex/subject-fixed.ts

@@ -0,0 +1 @@
+import { foo } from '@/foo/index.js';

tests/fixtures/requireExtension/pathsImportWithIndex/subject.ts

@@ -0,0 +1 @@
+import { foo } from '@/foo';

tests/fixtures/requireExtension/pathsImportWithIndex/tsconfig.json

@@ -0,0 +1,13 @@
+{
+  "compilerOptions": {
+    "baseUrl": ".",
+    "paths": {
+      "@/*": [
+        "*"
+      ]
+    }
+  },
+  "include": [
+    "."
+  ]
+}

tests/fixtures/requireExtension/relativeImport/foo.ts

@@ -0,0 +1 @@
+export const foo = 'FOO';

tests/fixtures/requireExtension/relativeImport/subject-fixed.ts

@@ -0,0 +1 @@
+import { foo } from './foo.js';

tests/fixtures/requireExtension/relativeImport/subject.ts

@@ -0,0 +1 @@
+import { foo } from './foo';

tests/fixtures/requireExtension/relativeImportWithExtension/foo.ts

@@ -0,0 +1 @@
+export const foo = 'FOO';

tests/fixtures/requireExtension/relativeImportWithExtension/subject.ts

@@ -0,0 +1 @@
+import { foo } from './foo.js';

tests/fixtures/requireExtension/relativeImportWithIndex/foo/index.ts

@@ -0,0 +1 @@
+export const foo = 'FOO';

tests/fixtures/requireExtension/relativeImportWithIndex/subject-fixed.ts

@@ -0,0 +1 @@
+import { foo } from './foo/index.js';

tests/fixtures/requireExtension/relativeImportWithIndex/subject.ts

@@ -0,0 +1 @@
+import { foo } from './foo';