[New]: add rule default-import-match-filename

Author: golopot

CHANGELOG.md

@@ -7,7 +7,8 @@ This change log adheres to standards from [Keep a CHANGELOG](http://keepachangel
 
 ### Added
 - [`group-exports`]: make aggregate module exports valid ([#1472], thanks [@atikenny])
-
+- `default`: make error message less confusing ([#1470], thanks [@golopot])
+- Add [`default-import-match-filename`] rule, ([#1476], thanks [@golopot])
 ### Added
 - support `parseForESLint` from custom parser ([#1435], thanks [@JounQin])
 
@@ -986,3 +987,4 @@ for info on changes for earlier releases.
 [@lencioni]: https://github.com/lencioni
 [@JounQin]: https://github.com/JounQin
 [@atikenny]: https://github.com/atikenny
+[@golopot]: https://github.com/golopot

README.md

@@ -94,6 +94,7 @@ 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 default import name to match filename ([`default-import-match-filename`])
 
 [`first`]: ./docs/rules/first.md
 [`exports-last`]: ./docs/rules/exports-last.md
@@ -111,6 +112,7 @@ 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
+[`default-import-match-filename`]: ./docs/rules/default-import-match-filename.md
 
 ## Support
 

docs/rules/default-import-match-filename.md

@@ -0,0 +1,27 @@
+# import/default-import-match-filename
+
+Enforces default import name to match filename. Name matching is case-insensitive, and characters `._-` are stripped.
+
+## Rule Details
+
+### Fail
+
+```js
+import bar from './foo';
+import utilsFoo from '../utils/foo';
+import foo from '../foo/index.js';
+const bar = require('./foo');
+const bar = require('../foo');
+```
+
+### Pass
+
+```js
+import foo from './foo';
+import foo_ from './foo';
+import foo from './foo.js';
+import fooBar from './foo-bar';
+import FoObAr from './foo-bar';
+import catModel from './cat.model.js';
+const foo = require('./foo');
+```

src/index.js

@@ -38,6 +38,7 @@ export const rules = {
   'unambiguous': require('./rules/unambiguous'),
   'no-unassigned-import': require('./rules/no-unassigned-import'),
   'no-useless-path-segments': require('./rules/no-useless-path-segments'),
+  'default-import-match-filename': require('./rules/default-import-match-filename'),
   'dynamic-import-chunkname': require('./rules/dynamic-import-chunkname'),
 
   // export

src/rules/default-import-match-filename.js

@@ -0,0 +1,120 @@
+import docsUrl from '../docsUrl'
+import isStaticRequire from '../core/staticRequire'
+
+/**
+ * @param {string} filename
+ * @returns {string}
+ */
+function removeExtension(filename) {
+  return filename.replace(/\.[^.]+$/, '')
+}
+
+/**
+ * @param {string} filename
+ * @returns {string}
+ */
+function normalizeFilename(filename) {
+  return filename.replace(/[-_.]/g, '').toLowerCase()
+}
+
+/**
+ * Test if local name matches filename.
+ * @param {string} localName
+ * @param {string} filename
+ * @returns {boolean}
+ */
+function isCompatible(localName, filename) {
+  const normalizedLocalName = localName.replace(/_/g, '').toLowerCase()
+
+  return (
+    normalizedLocalName === normalizeFilename(filename) ||
+    normalizedLocalName === normalizeFilename(removeExtension(filename))
+  )
+}
+
+/**
+ * Test if path starts with "./" or "../".
+ * @param {string} path
+ * @returns {boolean}
+ */
+function isLocalModule(path) {
+  return /^(\.\/|\.\.\/)/.test(path)
+}
+
+/**
+ * Get filename from a path.
+ * @param {string} path
+ * @returns {string | undefined}
+ */
+function getFilename(path) {
+  if (!isLocalModule(path)) return undefined
+  const [, filename] = /\/([^/]*)$/.exec(path)
+  if (filename === '' || filename === '.' || filename === '..') {
+    return undefined
+  }
+  return filename
+}
+
+module.exports = {
+  meta: {
+    type: 'suggestion',
+    docs: {
+      url: docsUrl('default-import-match-filename'),
+    },
+  },
+
+  create(context) {
+    return {
+      ImportDeclaration(node) {
+        const defaultImportSpecifier = node.specifiers.find(
+          ({type}) => type === 'ImportDefaultSpecifier'
+        )
+
+        const defaultImportName =
+          defaultImportSpecifier && defaultImportSpecifier.local.name
+
+        if (!defaultImportName) {
+          return
+        }
+
+        const filename = getFilename(node.source.value)
+
+        if (!filename) {
+          return
+        }
+
+        if (!isCompatible(defaultImportName, filename)) {
+          context.report({
+            node: defaultImportSpecifier,
+            message: `Default import name does not match filename "${filename}".`,
+          })
+        }
+      },
+
+      CallExpression(node) {
+        if (
+          !isStaticRequire(node) ||
+          node.parent.type !== 'VariableDeclarator' ||
+          node.parent.id.type !== 'Identifier'
+        ) {
+          return
+        }
+
+        const localName = node.parent.id.name
+
+        const filename = getFilename(node.arguments[0].value)
+
+        if (!filename) {
+          return
+        }
+
+        if (!isCompatible(localName, filename)) {
+          context.report({
+            node: node.parent.id,
+            message: `Default import name does not match filename "${filename}".`,
+          })
+        }
+      },
+    }
+  },
+}

tests/src/rules/default-import-match-filename.js

@@ -0,0 +1,77 @@
+import {RuleTester} from 'eslint'
+import rule from '../../../src/rules/default-import-match-filename' // eslint-disable-line import/default
+
+const ruleTester = new RuleTester({
+  parserOptions: {
+    sourceType: 'module',
+    ecmaVersion: 6,
+  },
+})
+
+function getMessage(filename) {
+  return `Default import name does not match filename "${filename}".`
+}
+
+function fail(code, filename) {
+  return {
+    code,
+    errors: [
+      {
+        message: getMessage(filename),
+      },
+    ],
+  }
+}
+
+ruleTester.run('default-import-match-filename', rule, {
+  valid: [
+    'import Cat from "./cat"',
+    'import cat from "./cat"',
+    'import cat from "./Cat"',
+    'import Cat from "./Cat"',
+    'import cat from "./cat.js"',
+    'import cat from "./cat.ts"',
+    'import cat from "./cat.jpeg"',
+    'import cat_ from "./cat"',
+    'import loudCat from "./loud-cat"',
+    'import LOUDCAT from "./loud-cat"',
+    'import loud_cat from "./loud-cat"',
+    'import loudcat from "./loud_cat"',
+    'import loud_cat from "./loud_cat"',
+    'import catModel from "./cat.model"',
+    'import catModel from "./cat.model.js"',
+    'import doge from "."',
+    'import doge from "./"',
+    'import doge from "./.."',
+    'import doge from "./../"',
+    'import doge from ".."',
+    'import doge from "../"',
+    'import doge from "../.."',
+    'import doge from "cat"',
+    'import doge from "loud-cat"',
+    'import doge from ".cat"',
+    'import doge from "/cat"',
+    'import doge from ""',
+    'import {doge} from "./cat"',
+    'import cat, {doge} from "./cat"',
+    'const cat = require("..")',
+    'const cat = require("./cat")',
+    'const cat = require("../cat")',
+    'const {f, g} = require("./cat")',
+  ],
+  invalid: [
+    fail('import cat0 from "./cat"', 'cat'),
+    fail('import catfish from "./cat"', 'cat'),
+    fail('import catfish, {cat} from "./cat"', 'cat'),
+    fail('import catModel from "./models/cat"', 'cat'),
+    fail('import cat from "./cat.model.js"', 'cat.model.js'),
+    fail('import cat from "./cat/index"', 'index'),
+    fail('import cat from "./cat/index.js"', 'index.js'),
+    fail('import cat from "../cat/index.js"', 'index.js'),
+    fail('import cat7 from "./cat8"', 'cat8'),
+    fail('const catfish = require("./cat")', 'cat'),
+    fail('const cat = require("./cat/index")', 'index'),
+    fail('const cat = require("./cat/index.js")', 'index.js'),
+    fail('const doge = require("../models/cat")', 'cat'),
+  ],
+})