[Fix] no-unused-modules: Exclude package "main"/"bin"/"browser" entry points

Fixes #1327.

Author: rfermann

docs/rules/no-unused-modules.md

@@ -105,7 +105,8 @@ export function doAnything() {
 export default 5 // will not be reported
 ```
 
-
+#### Important Note
+Exports from files listed as a main file (`main`, `browser`, or `bin` fields in `package.json`) will be ignored by default. This only applies if the `package.json` is not set to `private: true`
 
 ## When not to use
 

package.json

@@ -88,6 +88,7 @@
     "eslint-module-utils": "^2.4.0",
     "has": "^1.0.3",
     "minimatch": "^3.0.4",
+    "object.values": "^1.1.0",
     "read-pkg-up": "^2.0.0",
     "resolve": "^1.11.0"
   },

src/rules/no-unused-modules.js

@@ -7,6 +7,9 @@
 import Exports from '../ExportMap'
 import resolve from 'eslint-module-utils/resolve'
 import docsUrl from '../docsUrl'
+import { dirname, join } from 'path'
+import readPkgUp from 'read-pkg-up'
+import values from 'object.values'
 
 // eslint/lib/util/glob-util has been moved to eslint/lib/util/glob-utils with version 5.3
 // and has been moved to eslint/lib/cli-engine/file-enumerator in version 6
@@ -80,7 +83,7 @@ const prepareImportsAndExports = (srcFiles, context) => {
     if (currentExports) {
       const { dependencies, reexports, imports: localImportList, namespace  } = currentExports
 
-      // dependencies === export * from 
+      // dependencies === export * from
       const currentExportAll = new Set()
       dependencies.forEach(value => {
         currentExportAll.add(value().path)
@@ -146,7 +149,7 @@ const prepareImportsAndExports = (srcFiles, context) => {
 }
 
 /**
- * traverse through all imports and add the respective path to the whereUsed-list 
+ * traverse through all imports and add the respective path to the whereUsed-list
  * of the corresponding export
  */
 const determineUsage = () => {
@@ -201,6 +204,58 @@ const newNamespaceImportExists = specifiers =>
 const newDefaultImportExists = specifiers =>
   specifiers.some(({ type }) => type === IMPORT_DEFAULT_SPECIFIER)
 
+const fileIsInPkg = file => {
+  const { path, pkg } = readPkgUp.sync({cwd: file, normalize: false})
+  const basePath = dirname(path)
+
+  const checkPkgFieldString = pkgField => {
+    if (join(basePath, pkgField) === file) {
+        return true
+      }
+  }
+
+  const checkPkgFieldObject = pkgField => {
+      const pkgFieldFiles = values(pkgField).map(value => join(basePath, value))
+      if (pkgFieldFiles.includes(file)) {
+        return true
+      }
+  }
+
+  const checkPkgField = pkgField => {
+    if (typeof pkgField === 'string') {
+      return checkPkgFieldString(pkgField)
+    }
+
+    if (typeof pkgField === 'object') {
+      return checkPkgFieldObject(pkgField)
+    }
+  }
+
+  if (pkg.private === true) {
+    return false
+  }
+
+  if (pkg.bin) {
+    if (checkPkgField(pkg.bin)) {
+      return true
+    }
+  }
+
+  if (pkg.browser) {
+    if (checkPkgField(pkg.browser)) {
+      return true
+    }
+  }
+
+  if (pkg.main) {
+    if (checkPkgFieldString(pkg.main)) {
+      return true
+    }
+  }
+
+  return false
+}
+
 module.exports = {
   meta: {
     docs: { url: docsUrl('no-unused-modules') },
@@ -315,6 +370,10 @@ module.exports = {
         return
       }
 
+      if (fileIsInPkg(file)) {
+        return
+      }
+
       // refresh list of source files
       const srcFiles = resolveFiles(getSrc(src), ignoreExports)
 
@@ -325,7 +384,7 @@ module.exports = {
 
       exports = exportList.get(file)
 
-      // special case: export * from 
+      // special case: export * from
       const exportAll = exports.get(EXPORT_ALL_DECLARATION)
       if (typeof exportAll !== 'undefined' && exportedValue !== IMPORT_DEFAULT_SPECIFIER) {
         if (exportAll.whereUsed.size > 0) {
@@ -362,7 +421,7 @@ module.exports = {
 
     /**
      * only useful for tools like vscode-eslint
-     * 
+     *
      * update lists of existing exports during runtime
      */
     const updateExportUsage = node => {
@@ -384,7 +443,7 @@ module.exports = {
       node.body.forEach(({ type, declaration, specifiers }) => {
         if (type === EXPORT_DEFAULT_DECLARATION) {
           newExportIdentifiers.add(IMPORT_DEFAULT_SPECIFIER)
-        } 
+        }
         if (type === EXPORT_NAMED_DECLARATION) {
           if (specifiers.length > 0) {
             specifiers.forEach(specifier => {
@@ -399,7 +458,7 @@ module.exports = {
               declaration.type === CLASS_DECLARATION
             ) {
               newExportIdentifiers.add(declaration.id.name)
-            }   
+            }
             if (declaration.type === VARIABLE_DECLARATION) {
               declaration.declarations.forEach(({ id }) => {
                 newExportIdentifiers.add(id.name)
@@ -438,7 +497,7 @@ module.exports = {
 
     /**
      * only useful for tools like vscode-eslint
-     * 
+     *
      * update lists of existing imports during runtime
      */
     const updateImportUsage = node => {

tests/files/no-unused-modules/bin.js

@@ -0,0 +1 @@
+export const bin = 'bin'

tests/files/no-unused-modules/binObject/index.js

@@ -0,0 +1 @@
+export const binObject = 'binObject'

tests/files/no-unused-modules/binObject/package.json

@@ -0,0 +1,6 @@
+{
+  "bin": {
+    "binObject": "./index.js"
+  },
+  "private": false
+}

tests/files/no-unused-modules/browser.js

@@ -0,0 +1 @@
+export const browser = 'browser'

tests/files/no-unused-modules/browserObject/index.js

@@ -0,0 +1 @@
+export const browserObject = 'browserObject'

tests/files/no-unused-modules/browserObject/package.json

@@ -0,0 +1,5 @@
+{
+  "browser": {
+    "browserObject": "./index.js"
+  }
+}

tests/files/no-unused-modules/main/index.js

@@ -0,0 +1 @@
+export const main = 'main'

tests/files/no-unused-modules/package.json

@@ -0,0 +1,5 @@
+{
+  "bin": "./bin.js",
+  "browser": "./browser.js",
+  "main": "./main/index.js"
+}

tests/files/no-unused-modules/privatePkg/index.js

@@ -0,0 +1 @@
+export const privatePkg = 'privatePkg'

tests/files/no-unused-modules/privatePkg/package.json

@@ -0,0 +1,4 @@
+{
+  "main": "./index.js",
+  "private": true
+}

tests/src/rules/no-unused-modules.js

@@ -610,4 +610,32 @@ ruleTester.run('no-unused-modules', rule, {
             filename: testFilePath('../jsx/named.jsx')}),
   ],
   invalid: [],
-})
+})
+
+describe('do not report unused export for files mentioned in package.json', () => {
+  ruleTester.run('no-unused-modules', rule, {
+    valid: [
+      test({ options: unusedExportsOptions,
+             code: 'export const bin = "bin"',
+             filename: testFilePath('./no-unused-modules/bin.js')}),
+      test({ options: unusedExportsOptions,
+             code: 'export const binObject = "binObject"',
+             filename: testFilePath('./no-unused-modules/binObject/index.js')}),
+      test({ options: unusedExportsOptions,
+             code: 'export const browser = "browser"',
+             filename: testFilePath('./no-unused-modules/browser.js')}),
+      test({ options: unusedExportsOptions,
+             code: 'export const browserObject = "browserObject"',
+             filename: testFilePath('./no-unused-modules/browserObject/index.js')}),
+      test({ options: unusedExportsOptions,
+             code: 'export const main = "main"',
+             filename: testFilePath('./no-unused-modules/main/index.js')}),
+    ],
+    invalid: [
+      test({ options: unusedExportsOptions,
+             code: 'export const privatePkg = "privatePkg"',
+             filename: testFilePath('./no-unused-modules/privatePkg/index.js'),
+             errors: [error(`exported declaration 'privatePkg' not used within other modules`)]}),
+    ],
+  })
+})