Add rule to enforce default import aliases

Author: mic4ael

CHANGELOG.md

@@ -4,6 +4,7 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 This change log adheres to standards from [Keep a CHANGELOG](http://keepachangelog.com).
 
 ## [Unreleased]
+- Add [`rename-default-import`] rule: Enforce default import naming
 
 ## [2.13.0] - 2018-06-24
 ### Added
@@ -470,6 +471,7 @@ for info on changes for earlier releases.
 [`no-default-export`]: ./docs/rules/no-default-export.md
 [`no-useless-path-segments`]: ./docs/rules/no-useless-path-segments.md
 [`no-cycle`]: ./docs/rules/no-cycle.md
+[`rename-default-import`]: ./docs/rules/rename-default-import.md
 
 [`memo-parser`]: ./memo-parser/README.md
 

README.md

@@ -89,6 +89,7 @@ This plugin intends to support linting of ES2015+ (ES6+) import/export syntax, a
 * Forbid anonymous values as default exports ([`no-anonymous-default-export`])
 * Prefer named exports to be grouped together in a single export declaration ([`group-exports`])
 * Enforce a leading comment with the webpackChunkName for dynamic imports ([`dynamic-import-chunkname`])
+* Enforce an alias for the default package import ([`rename-default-import`])
 
 [`first`]: ./docs/rules/first.md
 [`exports-last`]: ./docs/rules/exports-last.md
@@ -105,6 +106,7 @@ This plugin intends to support linting of ES2015+ (ES6+) import/export syntax, a
 [`group-exports`]: ./docs/rules/group-exports.md
 [`no-default-export`]: ./docs/rules/no-default-export.md
 [`dynamic-import-chunkname`]: ./docs/rules/dynamic-import-chunkname.md
+[`rename-default-import`]: ./docs/rules/rename-default-import.md
 
 ## Installation
 

docs/rules/rename-default-import.md

@@ -0,0 +1,56 @@
+# import/rename-default-import
+
+This rule will enforce an alias for a default package import. Only ES6 imports are processed.
+
+
+## Rule Details
+
+Given:
+
+```js
+// ./foo.js
+export default function () { return 'Foo' }
+```
+
+and
+
+```yaml
+// .eslintrc
+rules:
+  import/rename-default-import:
+    - warn
+    - prop-types: PropTypes
+      Foo: Foo // default for package Foo should be aliased to Foo
+```
+
+The following is considered valid:
+
+```js
+import Foo from './foo'
+
+import {default as PropTypes} from 'prop-types'
+
+import PropTypes from 'prop-types'
+```
+
+...and the following cases are reported:
+
+```js
+import propTypes from 'prop-types';
+import {default as propTypes} from 'prop-types';
+```
+
+
+## When not to use it
+
+As long as you don't want to enforce specific naming for default imports.
+
+## Options
+
+This rule accepts an object which is a mapping
+between package names and the aliases that should be used for default imports.
+For example, a configuration like the one below
+
+`{'prop-types': 'PropTypes'}`
+
+specifies that default import for the package `prop-types` should be aliased to `PropTypes`.

src/index.js

@@ -37,6 +37,7 @@ export const rules = {
   'no-unassigned-import': require('./rules/no-unassigned-import'),
   'no-useless-path-segments': require('./rules/no-useless-path-segments'),
   'dynamic-import-chunkname': require('./rules/dynamic-import-chunkname'),
+  'rename-default-import': require('./rules/rename-default-import'),
 
   // export
   'exports-last': require('./rules/exports-last'),

src/rules/rename-default-import.js

@@ -0,0 +1,87 @@
+/**
+ * @fileoverview Rule to enforce aliases for default imports
+ * @author Michał Kołodziejski
+ */
+
+import docsUrl from '../docsUrl'
+
+
+function isDefaultImport(specifier) {
+  return specifier.type === 'ImportDefaultSpecifier' || specifier.imported.name === 'default'
+}
+
+
+function handleImport(context, specifier, source) {
+  const {value: packageName} = source
+  const {local: {name: importAlias}} = specifier
+  const mappings = context.options[0]
+
+  if (!Object.keys(mappings).includes(packageName)) {
+    return
+  }
+
+  if (mappings[packageName] !== importAlias) {
+    context.report({
+      node: source,
+      message: `Default import from '${packageName}' should be aliased to `
+               + `${mappings[packageName]}, not ${importAlias}`,
+      fix: fixer => {
+        let newAlias = mappings[packageName]
+        if (specifier.imported && specifier.imported.name === 'default') {
+          newAlias = `default as ${mappings[packageName]}`
+        }
+
+        return fixer.replaceText(specifier, newAlias)
+      },
+    })
+
+    const declaredVariable = context.getDeclaredVariables(specifier)[0]
+    for (const variableReference of declaredVariable.references) {
+      context.report({
+        node: variableReference.identifier,
+        message: `Using incorrect alias '${variableReference.identifier.name}' `
+                 + `instead of ${mappings[packageName]} for `
+                 + `default import from package ${packageName}`,
+        fix: fixer => {
+          return fixer.replaceText(variableReference.identifier, mappings[packageName])
+        },
+      })
+    }
+  }
+}
+
+
+module.exports = {
+  meta: {
+      docs: {
+          url: docsUrl('rename-default-import'),
+          recommended: false,
+      },
+      schema: [
+        {
+          type: 'object',
+        },
+      ],
+      fixable: 'code',
+  },
+  create: function(context) {
+      return {
+        'ImportDeclaration': function(node) {
+          const {source, specifiers} = node
+          const options = context.options
+
+          if (options.length === 0 || Object.keys(options[0]).length === 0) {
+            return
+          }
+
+          for (const specifier of specifiers) {
+            if (!isDefaultImport(specifier)) {
+              continue
+            }
+
+            handleImport(context, specifier, source)
+          }
+        },
+      }
+  },
+}

tests/src/rules/rename-default-import.js

@@ -0,0 +1,160 @@
+import { test } from '../utils'
+
+import { RuleTester } from 'eslint'
+
+const ruleTester = new RuleTester(),
+      rule = require('rules/rename-default-import')
+
+ruleTester.run('rename-default-import', rule, {
+  valid: [
+    test({
+      code: `
+        import PropTypes from 'prop-types';
+      `,
+      options: [],
+    }),
+    test({
+      code: `
+        import PropTypes from 'prop-types';
+      `,
+      options: [{'prop-types': 'PropTypes'}],
+    }),
+    test({
+      code: `
+        import PropTypes, {Foo} from 'prop-types';
+      `,
+      options: [{'prop-types': 'PropTypes'}],
+    }),
+    test({
+      code: `
+        import {default as PropTypes} from 'prop-types';
+      `,
+      options: [{'prop-types': 'PropTypes'}],
+    }),
+    test({
+      code: `
+        import {Foo} from 'prop-types';
+      `,
+      options: [{'prop-types': 'PropTypes'}],
+    }),
+  ],
+  invalid: [
+    test({
+      code: `import propTypes from 'prop-types';`,
+      options: [{'prop-types': 'PropTypes'}],
+      output: `import PropTypes from 'prop-types';`,
+      errors: [{
+        ruleId: 'rename-default-import',
+        message: `Default import from 'prop-types' should be aliased to PropTypes, not propTypes`,
+      }],
+    }),
+    test({
+      code: `import propTypes, {B} from 'prop-types';`,
+      options: [{'prop-types': 'PropTypes'}],
+      output: `import PropTypes, {B} from 'prop-types';`,
+      errors: [{
+        ruleId: 'rename-default-import',
+        message: `Default import from 'prop-types' should be aliased to PropTypes, not propTypes`,
+      }],
+    }),
+    test({
+      code: `import {default as propTypes} from 'prop-types';`,
+      options: [{'prop-types': 'PropTypes'}],
+      output: `import {default as PropTypes} from 'prop-types';`,
+      errors: [{
+        ruleId: 'rename-default-import',
+        message: `Default import from 'prop-types' should be aliased to PropTypes, not propTypes`,
+      }],
+    }),
+    test({
+      code: `import propTypes from 'prop-types';import foo from 'foo';`,
+      options: [{'prop-types': 'PropTypes', 'foo': 'Foo'}],
+      output: `import PropTypes from 'prop-types';import Foo from 'foo';`,
+      errors: [{
+        ruleId: 'rename-default-import',
+        message: `Default import from 'prop-types' should be aliased to PropTypes, not propTypes`,
+      }, {
+        ruleId: 'rename-default-import',
+        message: `Default import from 'foo' should be aliased to Foo, not foo`,
+      }],
+    }),
+    test({
+      code: `
+      import propTypes from 'prop-types';
+
+      const obj = {
+        foo: propTypes.string
+      }
+      `,
+      options: [{'prop-types': 'PropTypes'}],
+      output: `
+      import PropTypes from 'prop-types';
+
+      const obj = {
+        foo: PropTypes.string
+      }
+      `,
+      errors: [{
+        ruleId: 'rename-default-import',
+        message: `Default import from 'prop-types' should be aliased to PropTypes, not propTypes`,
+      }, {
+        ruleId: 'rename-default-import',
+        message: `Using incorrect alias 'propTypes' instead of PropTypes for default import from package prop-types`
+      }],
+    }),
+    test({
+      code: `
+      import foo from 'bar';
+      const a = foo.foo();
+      const b = bar(foo);
+      const c = (foo) => {
+          foo();
+      };
+      c(foo)
+      const d = (bar) => {
+          bar();
+      };
+      d(foo);
+      const e = () => {
+          foo();
+      };
+      `,
+      options: [{'bar': 'Foo'}],
+      output: `
+      import Foo from 'bar';
+      const a = Foo.foo();
+      const b = bar(Foo);
+      const c = (foo) => {
+          foo();
+      };
+      c(Foo)
+      const d = (bar) => {
+          bar();
+      };
+      d(Foo);
+      const e = () => {
+          Foo();
+      };
+      `,
+      errors: [{
+        ruleId: 'rename-default-import',
+        message: `Default import from 'bar' should be aliased to Foo, not foo`,
+      }, {
+        ruleId: 'rename-default-import',
+        message: `Using incorrect alias 'foo' instead of Foo for default import from package bar`,
+      }, {
+        ruleId: 'rename-default-import',
+        message: `Using incorrect alias 'foo' instead of Foo for default import from package bar`,
+      }, {
+        ruleId: 'rename-default-import',
+        message: `Using incorrect alias 'foo' instead of Foo for default import from package bar`,
+      }, {
+        ruleId: 'rename-default-import',
+        message: `Using incorrect alias 'foo' instead of Foo for default import from package bar`,
+      }, {
+        ruleId: 'rename-default-import',
+        message: `Using incorrect alias 'foo' instead of Foo for default import from package bar`,
+      }]
+    })
+  ]
+})