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

…ferent name

CHANGELOG.md

@@ -11,6 +11,7 @@ This change log adheres to standards from [Keep a CHANGELOG](https://keepachange
 - [`dynamic-import-chunkname`]: Allow empty chunk name when webpackMode: 'eager' is set; add suggestions to remove name in eager mode ([#3004], thanks [@amsardesai])
 - [`no-unused-modules`]: Add `ignoreUnusedTypeExports` option ([#3011], thanks [@silverwind])
 - add support for Flat Config ([#3018], thanks [@michaelfaith])
+- [`no-rename-default`]: Forbid importing a default export by a different name ([#3006], thanks [@whitneyit])
 
 ### Fixed
 - [`no-extraneous-dependencies`]: allow wrong path ([#3012], thanks [@chabb])

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

docs/rules/no-rename-default.md

@@ -0,0 +1,29 @@
+# import/no-rename-default
+
+<!-- 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

@@ -22,6 +22,7 @@ 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 +1,278 @@
+/**
+ * @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('eslint').Rule.RuleModule} */
+module.exports = {
+  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: {
+            default: false,
+            type: 'boolean',
+          },
+          preventRenamingBindings: {
+            default: true,
+            type: 'boolean',
+          },
+        },
+        additionalProperties: false,
+      },
+    ],
+  },
+
+  create(context) {
+    const {
+      commonjs = false,
+      preventRenamingBindings = true,
+    } = context.options[0] || {};
+
+    function getDefaultExportName(targetNode) {
+      if (targetNode == null) {
+        return;
+      }
+      switch (targetNode.type) {
+        case 'AssignmentExpression': {
+          if (!preventRenamingBindings) {
+            // Allow assignments to be renamed when the `preventRenamingBindings`
+            // option is set to `false`.
+            //
+            // export default Foo = 1;
+            return;
+          }
+          return targetNode.left.name;
+        }
+        case 'CallExpression': {
+          const [argumentNode] = targetNode.arguments;
+          return getDefaultExportName(argumentNode);
+        }
+        case 'ClassDeclaration': {
+          if (targetNode.id && typeof targetNode.id.name === 'string') {
+            return targetNode.id.name;
+          }
+          // Here we have an anonymous class. We can skip here.
+          return;
+        }
+        case 'ExportSpecifier': {
+          return targetNode.local.name;
+        }
+        case 'FunctionDeclaration': {
+          return targetNode.id.name;
+        }
+        case 'Identifier': {
+          if (!preventRenamingBindings) {
+            // Allow identifier to be renamed when the `preventRenamingBindings`
+            // option is set to `false`.
+            //
+            // const foo = 'foo';
+            // export default foo;
+            return;
+          }
+          return targetNode.name;
+        }
+        default:
+          // This type of node is not handled.
+          // Returning `undefined` here signifies this and causes the check to
+          // exit early.
+      }
+    }
+
+    function getDefaultExportNode(exportMap) {
+      const defaultExportNode = exportMap.exports.get('default');
+      if (defaultExportNode == null) {
+        return;
+      }
+
+      if (defaultExportNode.type === 'ExportDefaultDeclaration') {
+        return defaultExportNode.declaration;
+      }
+
+      if (defaultExportNode.type === 'ExportNamedDeclaration') {
+        return defaultExportNode.specifiers.find((specifier) => specifier.exported.name === 'default');
+      }
+    }
+
+    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;
+    }
+
+    function handleImport(node) {
+      const exportMap = getExportMap(node.parent.source, context);
+      if (exportMap == null) {
+        return;
+      }
+
+      const defaultExportNode = getDefaultExportNode(exportMap);
+      if (defaultExportNode == null) {
+        return;
+      }
+
+      const defaultExportName = getDefaultExportName(defaultExportNode);
+      if (defaultExportName === undefined) {
+        return;
+      }
+
+      const importTarget = node.parent.source.value;
+      const importBasename = path.basename(exportMap.path);
+
+      if (node.type === 'ImportDefaultSpecifier') {
+        const importName = node.local.name;
+
+        if (importName === defaultExportName) {
+          return;
+        }
+
+        context.report({
+          node,
+          message: `Caution: \`{{importBasename}}\` has a default export \`{{defaultExportName}}\`. This imports \`{{defaultExportName}}\` as \`{{importName}}\`. Check if you meant to write \`import {{defaultExportName} from '{{importTarget}}'\` instead.`,
+          data: {
+            defaultExportName,
+            importBasename,
+            importName,
+            importTarget,
+          },
+        });
+
+        return;
+      }
+
+      if (node.type !== 'ImportSpecifier' || node.imported.name !== 'default') {
+        return;
+      }
+
+      const actualImportedName = node.local.name;
+
+      if (actualImportedName === defaultExportName) {
+        return;
+      }
+
+      context.report({
+        node,
+        message: `Caution: \`{{importBasename}}\` has a default export \`{{defaultExportName}}\`. This imports \`{{defaultExportName}}\` as \`{{actualImportedName}}\`. Check if you meant to write \`import { default as {{defaultExportName}} } from '{{importTarget}}'\` instead.`,
+        data: {
+          actualImportedName,
+          defaultExportName,
+          importBasename,
+          importTarget,
+        },
+      });
+    }
+
+    function handleRequire(node) {
+      if (
+        !commonjs
+        || node.type !== 'VariableDeclarator'
+        || !node.id
+        || !(node.id.type === 'Identifier'
+        || node.id.type === 'ObjectPattern')
+        || !node.init
+        || node.init.type !== 'CallExpression'
+      ) {
+        return;
+      }
+
+      let defaultDestructure;
+      if (node.id.type === 'ObjectPattern') {
+        defaultDestructure = node.id.properties.find((property) => property.key.name === 'default');
+        if (defaultDestructure === undefined) {
+          return;
+        }
+      }
+
+      const call = node.init;
+      const [source] = call.arguments;
+
+      if (
+        call.callee.type !== 'Identifier'
+        || call.callee.name !== 'require'
+        || call.arguments.length !== 1
+        || 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.type === 'Identifier' ? node.id.name : defaultDestructure.value.name;
+
+      if (defaultExportName === undefined) {
+        return;
+      }
+
+      if (requireName === defaultExportName) {
+        return;
+      }
+
+      const data = {
+        defaultExportName,
+        requireBasename,
+        requireName,
+        requireTarget,
+      };
+
+      if (node.id.type === 'Identifier') {
+        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.`,
+          data,
+        });
+        return;
+      }
+
+      context.report({
+        node,
+        message: `Caution: \`{{requireBasename}}\` has a default export \`{{defaultExportName}\`. This requires \`{{defaultExportName}\` as \`{{requireName}}\`. Check if you meant to write \`const { default: {{defaultExportName}} } = require('{{requireTarget}}')\` instead.`,
+        data,
+      });
+    }
+
+    return {
+      ImportDefaultSpecifier(node) {
+        handleImport(node);
+      },
+      ImportSpecifier(node) {
+        handleImport(node);
+      },
+      VariableDeclarator(node) {
+        handleRequire(node);
+      },
+    };
+  },
+};

tests/files/no-rename-default/anonymous-arrow-async.js

@@ -0,0 +1 @@
+export default async () => {};

tests/files/no-rename-default/anonymous-arrow.js

@@ -0,0 +1 @@
+export default () => {};

tests/files/no-rename-default/anonymous-class.js

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

tests/files/no-rename-default/anonymous-object.js

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

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

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

tests/files/no-rename-default/assign-arrow-async.js

@@ -0,0 +1 @@
+export default arrowAsync = async () => {};

tests/files/no-rename-default/assign-arrow.js

@@ -0,0 +1 @@
+export default arrow = () => {};

tests/files/no-rename-default/assign-class-named.js

@@ -0,0 +1 @@
+export default User = class MyUser {}

tests/files/no-rename-default/assign-class.js

@@ -0,0 +1 @@
+export default User = class {}

tests/files/no-rename-default/assign-fn-named.js

@@ -0,0 +1 @@
+export default fn = function myFn() {};

tests/files/no-rename-default/assign-fn.js

@@ -0,0 +1 @@
+export default fn = function () {};

tests/files/no-rename-default/assign-generator-named.js

@@ -0,0 +1 @@
+export default generator = function* myGenerator() {};

tests/files/no-rename-default/assign-generator.js

@@ -0,0 +1 @@
+export default generator = function* () {};

tests/files/no-rename-default/class-user.js

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

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

@@ -0,0 +1,6 @@
+export const barNamed1 = 'bar-named-1';
+export const barNamed2 = 'bar-named-2';
+
+const bar = 'bar';
+
+export default bar;

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

@@ -0,0 +1,6 @@
+export const fooNamed1 = 'foo-named-1';
+export const fooNamed2 = 'foo-named-2';
+
+const foo = 'foo';
+
+export default foo;

tests/files/no-rename-default/fn-get-users-sync.js

@@ -0,0 +1 @@
+export default function getUsersSync() {}

tests/files/no-rename-default/fn-get-users.js

@@ -0,0 +1 @@
+export default async function getUsers() {}

tests/files/no-rename-default/generator-reader.js

@@ -0,0 +1 @@
+export default function* reader() {}

tests/files/no-rename-default/pr-3006-feedback/binding-const-rename-fn.js

@@ -0,0 +1,3 @@
+const foo = function bar() {};
+
+export default foo;

tests/files/no-rename-default/pr-3006-feedback/binding-fn-rename.js

@@ -0,0 +1,3 @@
+function bar() {}
+
+export default bar;

tests/files/no-rename-default/pr-3006-feedback/binding-hoc-with-logger-for-foo.js

@@ -0,0 +1,4 @@
+import foo from '../default-const-foo';
+import withLogger from './hoc-with-logger';
+
+export default withLogger(foo);

tests/files/no-rename-default/pr-3006-feedback/binding-hoc-with-logger-for-get-users.js

@@ -0,0 +1,4 @@
+import getUsers from '../default-fn-get-users';
+import withLogger from './hoc-with-logger';
+
+export default withLogger(getUsers);