feat: port eslint-plugin-barrel-files

This ports the rules from `eslint-plugin-barrel-files` into the package.

Author: 43081j

LICENSE

@@ -1,6 +1,7 @@
 The MIT License (MIT)
 
 Copyright (c) 2015 Ben Mosher
+Copyright (c) 2020 modern-webdev
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

docs/rules/avoid-barrel-files.md

@@ -0,0 +1,27 @@
+# import-x/avoid-barrel-files
+
+This rule disallows _authoring_ barrel files in your project.
+
+## Rule Details
+
+Examples of **incorrect** code for this rule:
+
+```js
+export { foo } from 'foo'
+export { bar } from 'bar'
+export { baz } from 'baz'
+```
+
+## Options
+
+This rule has the following options, with these defaults:
+
+```js
+"import-x/avoid-barrel-files": ["error", {
+  "amountOfExportsToConsiderModuleAsBarrel": 5
+}]
+```
+
+### `amountOfExportsToConsiderModuleAsBarrel`
+
+This option sets the number of exports that will be considered a barrel file. Anything over will trigger the rule.

docs/rules/avoid-importing-barrel-files.md

@@ -0,0 +1,82 @@
+# import-x/avoid-importing-barrel-files
+
+This rule aims to avoid importing barrel files that lead to loading large module graphs. This rule is different from the `avoid-barrel-files` rule, which lints against _authoring_ barrel files. This rule lints against _importing_ barrel files.
+
+## Rule Details
+
+Examples of **incorrect** code for this rule:
+
+```js
+// If `foo` is a barrel file leading to a module graph of more than 20 modules
+export { foo } from 'foo'
+```
+
+## Options
+
+This rule has the following options, with these defaults:
+
+```js
+"import-x/avoid-importing-barrel-files": ["error", {
+  allowList: [],
+  maxModuleGraphSizeAllowed: 20,
+  amountOfExportsToConsiderModuleAsBarrel: 3,
+  debug: false,
+  exportConditions: ["node", "import"],
+  mainFields: ["module", "browser", "main"],
+  extensions: [".js", ".ts", ".tsx", ".jsx", ".json", ".node"],
+}]
+```
+
+### `allowList`
+
+List of modules from which to allow barrel files being imported.
+
+### `maxModuleGraphSizeAllowed`
+
+Maximum allowed module graph size. If an imported module results in loading more than this many modules, it will be considered a barrel file.
+
+### `amountOfExportsToConsiderModuleAsBarrel`
+
+Amount of exports to consider a module as a barrel file.
+
+### `exportConditions`
+
+Export conditions to use when resolving modules.
+
+### `mainFields`
+
+Main fields to use when resolving modules.
+
+### `extensions`
+
+Extensions to use when resolving modules.
+
+### `tsconfig`
+
+TSConfig options to pass to the underlying resolver when resolving modules.
+
+This can be useful when resolving project references in TypeScript.
+
+### `alias`
+
+The rule can accept an `alias` option whose value can be an object that matches Webpack's [resolve.alias](https://webpack.js.org/configuration/resolve/) configuration.
+
+```js
+// .eslintrc.cjs
+const path = require('path')
+
+export default {
+  // ...
+  rules: {
+    'barrel-files/avoid-importing-barrel-files': [
+      2,
+      {
+        alias: {
+          // "@/foo/bar.js" => "./src/foo/bar.js"
+          '@': [path.resolve('.', 'src')],
+        },
+      },
+    ],
+  },
+}
+```

docs/rules/avoid-namespace-import.md

@@ -0,0 +1,25 @@
+# import-x/avoid-namespace-import
+
+This rule forbids the use of namespace imports as they can lead to unused imports and prevent treeshaking.
+
+## Rule Details
+
+Examples of **incorrect** code for this rule:
+
+```js
+import * as foo from 'foo'
+```
+
+## Options
+
+This rule has the following options, with these defaults:
+
+```js
+"import-x/avoid-barrel-files": ["error", {
+  allowList: []
+}]
+```
+
+### `allowList`
+
+A list of namespace imports that are allowed.

docs/rules/avoid-re-export-all.md

@@ -0,0 +1,12 @@
+# import-x/avoid-re-export-all
+
+This rule forbids exporting `*` from a module as it can lead to unused imports and prevent treeshaking.
+
+## Rule Details
+
+Examples of **incorrect** code for this rule:
+
+```js
+export * from 'foo'
+export * as foo from 'foo'
+```

package.json

@@ -74,6 +74,7 @@
     "@typescript-eslint/utils": "^8.31.0",
     "comment-parser": "^1.4.1",
     "debug": "^4.4.0",
+    "eslint-barrel-file-utils": "^0.0.11",
     "eslint-import-resolver-node": "^0.3.9",
     "get-tsconfig": "^4.10.0",
     "is-glob": "^4.0.3",

src/index.ts

@@ -20,6 +20,10 @@ import warnings from './config/warnings.js'
 import { meta } from './meta.js'
 import { createNodeResolver } from './node-resolver.js'
 import { cjsRequire } from './require.js'
+import avoidBarrelFiles from './rules/avoid-barrel-files.js'
+import avoidImportingBarrelFiles from './rules/avoid-importing-barrel-files.js'
+import avoidNamespaceImport from './rules/avoid-namespace-import.js'
+import avoidReExportAll from './rules/avoid-re-export-all.js'
 import consistentTypeSpecifierStyle from './rules/consistent-type-specifier-style.js'
 import default_ from './rules/default.js'
 import dynamicImportChunkname from './rules/dynamic-import-chunkname.js'
@@ -129,6 +133,12 @@ const rules = {
 
   // deprecated aliases to rules
   'imports-first': importsFirst,
+
+  // barrel files
+  'avoid-barrel-files': avoidBarrelFiles,
+  'avoid-importing-barrel-files': avoidImportingBarrelFiles,
+  'avoid-namespace-import': avoidNamespaceImport,
+  'avoid-re-export-all': avoidReExportAll,
 } satisfies Record<string, TSESLint.RuleModule<string, readonly unknown[]>>
 
 const configs = {

src/rules/avoid-barrel-files.ts

@@ -0,0 +1,100 @@
+import { createRule } from '../utils/index.js'
+
+export interface Options {
+  amountOfExportsToConsiderModuleAsBarrel: number
+}
+
+export type MessageId = 'avoidBarrel'
+
+const defaultOptions: Options = {
+  amountOfExportsToConsiderModuleAsBarrel: 3,
+}
+
+export default createRule<[Options?], MessageId>({
+  name: 'avoid-barrel-files',
+  meta: {
+    type: 'suggestion',
+    docs: {
+      description: 'Forbid authoring of barrel files.',
+      category: 'Performance',
+      recommended: true,
+    },
+    schema: [
+      {
+        type: 'object',
+        properties: {
+          amountOfExportsToConsiderModuleAsBarrel: {
+            type: 'number',
+            description:
+              'Minimum amount of exports to consider module as barrelfile',
+            default: 3,
+          },
+        },
+        additionalProperties: false,
+      },
+    ],
+    messages: {
+      avoidBarrel:
+        'Avoid barrel files, they slow down performance, and cause large module graphs with modules that go unused.',
+    },
+  },
+  defaultOptions: [defaultOptions],
+  create(context) {
+    const options = context.options[0] || defaultOptions
+    const amountOfExportsToConsiderModuleAsBarrel =
+      options.amountOfExportsToConsiderModuleAsBarrel
+
+    return {
+      Program(node) {
+        let declarations = 0
+        let exports = 0
+
+        for (const n of node.body) {
+          if (n.type === 'VariableDeclaration') {
+            declarations += n.declarations.length
+          }
+
+          if (
+            n.type === 'FunctionDeclaration' ||
+            n.type === 'ClassDeclaration' ||
+            n.type === 'TSTypeAliasDeclaration' ||
+            n.type === 'TSInterfaceDeclaration'
+          ) {
+            declarations += 1
+          }
+
+          if (n.type === 'ExportNamedDeclaration') {
+            exports += n.specifiers.length
+          }
+
+          if (n.type === 'ExportAllDeclaration' && n?.exportKind !== 'type') {
+            exports += 1
+          }
+
+          if (n.type === 'ExportDefaultDeclaration') {
+            if (
+              n.declaration.type === 'FunctionDeclaration' ||
+              n.declaration.type === 'CallExpression'
+            ) {
+              declarations += 1
+            } else if (n.declaration.type === 'ObjectExpression') {
+              exports += n.declaration.properties.length
+            } else {
+              exports += 1
+            }
+          }
+        }
+
+        if (
+          exports > declarations &&
+          exports > amountOfExportsToConsiderModuleAsBarrel
+        ) {
+          context.report({
+            node,
+            messageId: 'avoidBarrel',
+          })
+        }
+      },
+    }
+  },
+})