[New] no-rename-default: Forbid importing a default export by a dif…

…ferent name

CHANGELOG.md

@@ -8,6 +8,7 @@ This change log adheres to standards from [Keep a CHANGELOG](https://keepachange
 
 ### Added
 - [`dynamic-import-chunkname`]: add `allowEmpty` option to allow empty leading comments ([#2942], thanks [@JiangWeixian])
+- [`no-rename-default`]: Forbid importing a default export by a different name ([#3006], thanks [@whitneyit])
 
 ### Changed
 - [Docs] `no-extraneous-dependencies`: Make glob pattern description more explicit ([#2944], thanks [@mulztob])

README.md

@@ -37,6 +37,7 @@ This plugin intends to support linting of ES2015+ (ES6+) import/export syntax, a
 | [no-mutable-exports](docs/rules/no-mutable-exports.md)                 | Forbid the use of mutable exports with `var` or `let`.                                |      |       |    |    |    |    |
 | [no-named-as-default](docs/rules/no-named-as-default.md)               | Forbid use of exported name as identifier of default export.                          |      | ☑️ 🚸 |    |    |    |    |
 | [no-named-as-default-member](docs/rules/no-named-as-default-member.md) | Forbid use of exported name as property of default export.                            |      | ☑️ 🚸 |    |    |    |    |
+| [no-rename-default](docs/rules/no-rename-default.md)                   | Forbid importing a default export by a different name.                                |      | 🚸    |    |    |    |    |
 | [no-unused-modules](docs/rules/no-unused-modules.md)                   | Forbid modules without exports, or exports without matching import in another module. |      |       |    |    |    |    |
 
 ### Module systems

config/warnings.js

@@ -7,6 +7,7 @@ module.exports = {
   rules: {
     'import/no-named-as-default': 1,
     'import/no-named-as-default-member': 1,
+    'import/no-rename-default': 1,
     'import/no-duplicates': 1,
   },
 };

docs/rules/no-rename-default.md

@@ -0,0 +1,31 @@
+# import/no-rename-default
+
+⚠️ This rule _warns_ in the 🚸 `warnings` config.
+
+<!-- end auto-generated rule header -->
+
+Prohibit importing a default export by another name.
+
+## Rule Details
+
+Given:
+
+```js
+// api/get-users.js
+export default async function getUsers() {}
+```
+
+...this would be valid:
+
+```js
+import getUsers from './api/get-users.js';
+```
+
+...and the following would be reported:
+
+```js
+// Caution: `get-users.js` has a default export `getUsers`.
+// This imports `getUsers` as `findUsers`.
+// Check if you meant to write `import getUsers from './api/get-users'` instead.
+import findUsers from './get-users';
+```

src/index.js

@@ -20,6 +20,7 @@ export const rules = {
   'no-named-as-default': require('./rules/no-named-as-default'),
   'no-named-as-default-member': require('./rules/no-named-as-default-member'),
   'no-anonymous-default-export': require('./rules/no-anonymous-default-export'),
+  'no-rename-default': require('./rules/no-rename-default'),
   'no-unused-modules': require('./rules/no-unused-modules'),
 
   'no-commonjs': require('./rules/no-commonjs'),

src/rules/no-rename-default.js

@@ -0,0 +1,157 @@
+/**
+ * @fileOverview Rule to warn about importing a default export by different name
+ * @author James Whitney
+ */
+
+import docsUrl from '../docsUrl';
+import ExportMapBuilder from '../exportMap/builder';
+import path from 'path';
+
+//------------------------------------------------------------------------------
+// Rule Definition
+//------------------------------------------------------------------------------
+
+/** @type {import('@typescript-eslint/utils').TSESLint.RuleModule} */
+const rule = {
+  meta: {
+    type: 'suggestion',
+    docs: {
+      category: 'Helpful warnings',
+      description: 'Forbid importing a default export by a different name.',
+      recommended: false,
+      url: docsUrl('no-named-as-default'),
+    },
+    schema: [
+      {
+        type: 'object',
+        properties: {
+          commonjs: {
+            type: 'boolean',
+          },
+        },
+        additionalProperties: false,
+      },
+    ],
+  },
+
+  create(context) {
+    function getDefaultExportName(defaultExportNode) {
+      return defaultExportNode.declaration.name;
+    }
+
+    function getDefaultExportNode(exportMap) {
+      const defaultExportNode = exportMap.exports.get('default');
+      if (defaultExportNode == null) {
+        return;
+      }
+      return defaultExportNode;
+    }
+
+    function getExportMap(source, context) {
+      const exportMap = ExportMapBuilder.get(source.value, context);
+      if (exportMap == null) {
+        return;
+      }
+      if (exportMap.errors.length > 0) {
+        exportMap.reportErrors(context, source.value);
+        return;
+      }
+      return exportMap;
+    }
+
+    return {
+      ImportDeclaration(node) {
+        const exportMap = getExportMap(node.source, context);
+        if (exportMap == null) {
+          return;
+        }
+
+        const defaultExportNode = getDefaultExportNode(exportMap);
+        if (defaultExportNode == null) {
+          return;
+        }
+
+        const defaultExportName = getDefaultExportName(defaultExportNode);
+        const importTarget = node.source.value;
+        const importBasename = path.basename(exportMap.path);
+
+        node.specifiers.forEach((importClause) => {
+          const importName = importClause.local.name;
+
+          // No named default export
+          if (defaultExportName === undefined) {
+            return;
+          }
+
+          // The name of the import matches the name of the default export.
+          if (importName === defaultExportName) {
+            return;
+          }
+
+          context.report({
+            node: importClause,
+            message: `Caution: \`${importBasename}\` has a default export \`${defaultExportName}\`. This imports \`${defaultExportName}\` as \`${importName}\`. Check if you meant to write \`import ${defaultExportName} from '${importTarget}'\` instead.`,
+          });
+        });
+      },
+      VariableDeclarator(node) {
+        const options = context.options[0] || {};
+
+        if (
+          !options.commonjs
+          || node.type !== 'VariableDeclarator'
+          // return if it's not an object destructure or it's an empty object destructure
+          || !node.id || node.id.type !== 'Identifier'
+          // return if there is no call expression on the right side
+          || !node.init || node.init.type !== 'CallExpression'
+        ) {
+          return;
+        }
+
+        const call = node.init;
+        const [source] = call.arguments;
+
+        if (
+          // return if it's not a commonjs require statement
+          call.callee.type !== 'Identifier' || call.callee.name !== 'require' || call.arguments.length !== 1
+          // return if it's not a string source
+          || source.type !== 'Literal'
+        ) {
+          return;
+        }
+
+        const exportMap = getExportMap(source, context);
+        if (exportMap == null) {
+          return;
+        }
+
+        const defaultExportNode = getDefaultExportNode(exportMap);
+        if (defaultExportNode == null) {
+          return;
+        }
+
+        const defaultExportName = getDefaultExportName(defaultExportNode);
+        const requireTarget = source.value;
+        const requireBasename = path.basename(exportMap.path);
+        const requireName = node.id.name;
+
+        // No named default export
+        if (defaultExportName === undefined) {
+          return;
+        }
+
+        // The name of the require matches the name of the default export.
+        if (requireName === defaultExportName) {
+          return;
+        }
+
+        context.report({
+          node,
+          message: `Caution: \`${requireBasename}\` has a default export \`${defaultExportName}\`. This requires \`${defaultExportName}\` as \`${requireName}\`. Check if you meant to write \`const ${defaultExportName} = require('${requireTarget}')\` instead.`,
+        });
+      },
+    };
+  },
+};
+
+module.exports = rule;

tests/files/no-rename-default/anon.js

@@ -0,0 +1 @@
+export default {};

tests/files/no-rename-default/named-bar.js

@@ -0,0 +1,3 @@
+const bar = 'bar';
+
+export default bar;

tests/files/no-rename-default/named-foo.js

@@ -0,0 +1,3 @@
+const foo = 'foo';
+
+export default foo;

tests/files/no-rename-default/primitive.js

@@ -0,0 +1 @@
+export default 123;

tests/src/rules/no-rename-default.js

@@ -0,0 +1,94 @@
+import { RuleTester } from 'eslint';
+import { test } from '../utils';
+
+const ruleTester = new RuleTester();
+const rule = require('rules/no-rename-default');
+
+ruleTester.run('no-rename-default', rule, {
+  valid: [
+    test({
+      code: `
+        import _ from './no-rename-default/anon.js'
+      `,
+    }),
+    test({
+      code: `
+        import bar from './no-rename-default/named-bar'
+        import foo from './no-rename-default/named-foo'
+      `,
+    }),
+    test({
+      code: `
+        import _ from './no-rename-default/primitive'
+      `,
+    }),
+    test({
+      code: `
+        const _ = require('./no-rename-default/anon.js')
+      `,
+      options: [{ commonjs: true }],
+    }),
+    test({
+      code: `
+        const bar = require('./no-rename-default/named-bar')
+        const foo = require('./no-rename-default/named-foo')
+      `,
+      options: [{ commonjs: true }],
+    }),
+    test({
+      code: `
+        const _ = require('./no-rename-default/primitive')
+      `,
+      options: [{ commonjs: true }],
+    }),
+  ],
+
+  invalid: [
+    test({
+      code: `
+        import bar from './no-rename-default/named-foo'
+      `,
+      errors: [{
+        message: 'Caution: `named-foo.js` has a default export `foo`. This imports `foo` as `bar`. Check if you meant to write `import foo from \'./no-rename-default/named-foo\'` instead.',
+        type: 'ImportDefaultSpecifier',
+      }],
+    }),
+    test({
+      code: `
+        import foo from './no-rename-default/named-bar'
+        import bar from './no-rename-default/named-foo'
+      `,
+      errors: [{
+        message: 'Caution: `named-bar.js` has a default export `bar`. This imports `bar` as `foo`. Check if you meant to write `import bar from \'./no-rename-default/named-bar\'` instead.',
+        type: 'ImportDefaultSpecifier',
+      }, {
+        message: 'Caution: `named-foo.js` has a default export `foo`. This imports `foo` as `bar`. Check if you meant to write `import foo from \'./no-rename-default/named-foo\'` instead.',
+        type: 'ImportDefaultSpecifier',
+      }],
+    }),
+    test({
+      code: `
+        const bar = require('./no-rename-default/named-foo')
+      `,
+      options: [{ commonjs: true }],
+      errors: [{
+        message: 'Caution: `named-foo.js` has a default export `foo`. This requires `foo` as `bar`. Check if you meant to write `const foo = require(\'./no-rename-default/named-foo\')` instead.',
+        type: 'VariableDeclarator',
+      }],
+    }),
+    test({
+      code: `
+        const foo = require('./no-rename-default/named-bar')
+        const bar = require('./no-rename-default/named-foo')
+      `,
+      options: [{ commonjs: true }],
+      errors: [{
+        message: 'Caution: `named-bar.js` has a default export `bar`. This requires `bar` as `foo`. Check if you meant to write `const bar = require(\'./no-rename-default/named-bar\')` instead.',
+        type: 'VariableDeclarator',
+      }, {
+        message: 'Caution: `named-foo.js` has a default export `foo`. This requires `foo` as `bar`. Check if you meant to write `const foo = require(\'./no-rename-default/named-foo\')` instead.',
+        type: 'VariableDeclarator',
+      }],
+    }),
+  ],
+});