Add rule to enforce default import aliases

Author: mic4ael

CHANGELOG.md

@@ -4,15 +4,17 @@ 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
+
 ### Fixed
 - [`no-extraneous-dependencies`]: `packageDir` option with array value was clobbering package deps instead of merging them ([#1175]/[#1176], thanks [@aravindet] & [@pzhine])
 
 
 ## [2.14.0] - 2018-08-13
 *   69e0187 (HEAD -> master, source/master, origin/master, origin/HEAD) Merge pull request #1151 from jf248/jsx
-|\  
+|\
 | * e30a757 (source/pr/1151, fork/jsx) Add JSX check to namespace rule
-|/  
+|/
 * 8252344 (source/pr/1148) Add error to output when module loaded as resolver has invalid API
 ### Added
 - [`no-useless-path-segments`]: add commonJS (CJS) support ([#1128], thanks [@1pete])
@@ -493,6 +495,7 @@ 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

@@ -90,6 +90,7 @@ 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 a specific binding name for the default package import ([`rename-default-import`])
 
 [`first`]: ./docs/rules/first.md
 [`exports-last`]: ./docs/rules/exports-last.md
@@ -107,6 +108,7 @@ This plugin intends to support linting of ES2015+ (ES6+) import/export syntax, a
 [`no-default-export`]: ./docs/rules/no-default-export.md
 [`no-named-export`]: ./docs/rules/no-named-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 a specific binding name for a default package import.
+Works for ES6 imports and CJS require.
+
+
+## Rule Details
+
+Given:
+
+There is a package `prop-types` with a default export
+
+and
+
+```json
+// .eslintrc
+{
+  "rules": {
+    "import/rename-default-import": [
+      "warn", {
+        "prop-types": "PropTypes", // key: name of the module, value: desired binding for default import
+      }
+    ]
+  }
+}
+```
+
+The following is considered valid:
+
+```js
+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 name and the binding name 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

@@ -38,6 +38,7 @@ 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 +1,142 @@
+/**
+ * @fileoverview Rule to enforce aliases for default imports
+ * @author Michał Kołodziejski
+ */
+
+import docsUrl from '../docsUrl'
+
+
+function isDefaultImport(specifier) {
+  if (specifier.type === 'ImportDefaultSpecifier') {
+    return true
+  } else if (specifier.type === 'ImportSpecifier' && specifier.imported.name === 'default') {
+    return true
+  }
+  return false
+}
+
+function isCommonJSImport(declaration) {
+  const variableInit = declaration.init
+  if (variableInit.type === 'CallExpression') {
+    return variableInit.callee.name === 'require'
+  }
+  return false
+}
+
+function handleImport(context, node, specifierOrDeclaration, packageName, importAlias) {
+  const mappings = context.options[0] || {}
+  const expectedAlias = mappings[packageName]
+
+  if (expectedAlias === undefined || expectedAlias === importAlias) {
+    return
+  }
+
+  context.report({
+    node: node,
+    message: `Default import from '${packageName}' should be aliased to `
+            + `${mappings[packageName]}, not ${importAlias}`,
+    fix: fixImportOrRequire(specifierOrDeclaration, mappings[packageName]),
+  })
+
+  let declaredVariables
+  if (specifierOrDeclaration.type === 'VariableDeclarator') {
+    declaredVariables = context.getDeclaredVariables(specifierOrDeclaration.parent)[0]
+  } else {
+    declaredVariables = context.getDeclaredVariables(specifierOrDeclaration)[0]
+  }
+
+  for (const variableReference of declaredVariables.references) {
+    if (specifierOrDeclaration.type === 'VariableDeclarator' && variableReference.init) {
+      continue
+    }
+
+    context.report({
+      node: variableReference.identifier,
+      message: `Using incorrect binding name '${variableReference.identifier.name}' `
+              + `instead of ${mappings[packageName]} for `
+              + `default import from package ${packageName}`,
+      fix: fixer => {
+        if (variableReference.identifier.parent.type !== 'ExportSpecifier') {
+          return fixer.replaceText(variableReference.identifier, mappings[packageName])
+        }
+      },
+    })
+  }
+}
+
+function fixImportOrRequire(node, text) {
+  return function(fixer) {
+    let newAlias = text
+    let nodeOrToken
+    if (node.type === 'VariableDeclarator') {
+      nodeOrToken = node.id
+      newAlias = text
+    } else {
+      nodeOrToken = node
+      if (node.imported && node.imported.name === 'default') {
+        newAlias = `default as ${text}`
+      } else {
+        newAlias = text
+      }
+    }
+
+    return fixer.replaceText(nodeOrToken, newAlias)
+  }
+}
+
+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
+
+        if (options.length === 0 || Object.keys(options[0]).length === 0) {
+          return
+        }
+
+        for (const specifier of specifiers) {
+          if (!isDefaultImport(specifier)) {
+            continue
+          }
+
+          handleImport(context, source, specifier, source.value, specifier.local.name)
+        }
+      },
+      'VariableDeclaration': function(node) {
+        const {declarations} = node
+        const {options} = context
+
+        if (options.length === 0 || Object.keys(options[0]).length === 0) {
+          return
+        }
+
+        for (const declaration of declarations) {
+          if (!isCommonJSImport(declaration)) {
+            continue
+          }
+
+          handleImport(
+            context,
+            node,
+            declaration,
+            declaration.init.arguments[0].value,
+            declaration.id.name
+          )
+        }
+      },
+    }
+  },
+}