no-extraneous-dependencies: add support/option for `peerDependencie…

…s` (#423)

CHANGELOG.md

@@ -4,6 +4,8 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 This change log adheres to standards from [Keep a CHANGELOG](http://keepachangelog.com).
 
 ## [Unreleased]
+### Added
+- Added an `peerDependencies` option to [`no-extraneous-dependencies`] to allow/forbid peer dependencies ([#423]).
 ### Fixed
 - removing `Symbol` dependencies (i.e. `for-of` loops) due to Node 0.10 polyfill
   issue (see [#415]). Should not make any discernible semantic difference.
@@ -249,6 +251,7 @@ for info on changes for earlier releases.
 [`prefer-default-export`]: ./docs/rules/prefer-default-export.md
 [`no-restricted-paths`]: ./docs/rules/no-restricted-paths.md
 
+[#NAN]: https://github.com/benmosher/eslint-plugin-import/pull/NAN
 [#395]: https://github.com/benmosher/eslint-plugin-import/pull/395
 [#371]: https://github.com/benmosher/eslint-plugin-import/pull/371
 [#365]: https://github.com/benmosher/eslint-plugin-import/pull/365
@@ -282,6 +285,7 @@ for info on changes for earlier releases.
 [#157]: https://github.com/benmosher/eslint-plugin-import/pull/157
 [#314]: https://github.com/benmosher/eslint-plugin-import/pull/314
 
+[#423]: https://github.com/benmosher/eslint-plugin-import/issues/423
 [#415]: https://github.com/benmosher/eslint-plugin-import/issues/415
 [#386]: https://github.com/benmosher/eslint-plugin-import/issues/386
 [#373]: https://github.com/benmosher/eslint-plugin-import/issues/373

docs/rules/no-extraneous-dependencies.md

@@ -1,6 +1,6 @@
 # Forbid the use of extraneous packages
 
-Forbid the import of external modules that are not declared in the `package.json`'s `dependencies` or `devDependencies`.
+Forbid the import of external modules that are not declared in the `package.json`'s `dependencies`, `devDependencies`, `optionalDependencies` or `peerDependencies`.
 The closest parent `package.json` will be used. If no `package.json` is found, the rule will not lint anything.
 
 ### Options
@@ -9,11 +9,12 @@ This rule supports the following options:
 
 `devDependencies`: If set to `false`, then the rule will show an error when `devDependencies` are imported. Defaults to `true`.
 `optionalDependencies`: If set to `false`, then the rule will show an error when `optionalDependencies` are imported. Defaults to `true`.
+`peerDependencies`: If set to `false`, then the rule will show an error when `peerDependencies` are imported. Defaults to `false`.
 
 You can set the options like this:
 
 ```js
-"import/no-extraneous-dependencies": ["error", {"devDependencies": false, "optionalDependencies": false}]
+"import/no-extraneous-dependencies": ["error", {"devDependencies": false, "optionalDependencies": false, "peerDependencies": false}]
 ```
 
 
@@ -38,6 +39,9 @@ Given the following `package.json`:
   },
   "optionalDependencies": {
     "lodash.isarray": "^4.0.0"
+  },
+  "peerDependencies": {
+    "react": ">=15.0.0 <16.0.0"
   }
 }
 ```
@@ -49,6 +53,8 @@ Given the following `package.json`:
 var _ = require('lodash');
 import _ from 'lodash';
 
+import react from 'react';
+
 /* eslint import/no-extraneous-dependencies: ["error", {"devDependencies": false}] */
 import test from 'ava';
 var test = require('ava');
@@ -69,6 +75,9 @@ var foo = require('./foo');
 import test from 'ava';
 import find from 'lodash.find';
 import find from 'lodash.isarray';
+
+/* eslint import/no-extraneous-dependencies: ["error", {"peerDependencies": true}] */
+import react from 'react';
 ```
 
 

src/rules/no-extraneous-dependencies.js

@@ -15,6 +15,7 @@ function getDependencies(context) {
       dependencies: packageContent.dependencies || {},
       devDependencies: packageContent.devDependencies || {},
       optionalDependencies: packageContent.optionalDependencies || {},
+      peerDependencies: packageContent.peerDependencies || {},
     }
   } catch (e) {
     return null
@@ -35,7 +36,7 @@ function optDepErrorMessage(packageName) {
     `not optionalDependencies.`
 }
 
-function reportIfMissing(context, deps, allowDevDeps, allowOptDeps, node, name) {
+function reportIfMissing(context, deps, depsOptions, node, name) {
   if (importType(name, context) !== 'external') {
     return
   }
@@ -47,20 +48,22 @@ function reportIfMissing(context, deps, allowDevDeps, allowOptDeps, node, name)
   const isInDeps = deps.dependencies[packageName] !== undefined
   const isInDevDeps = deps.devDependencies[packageName] !== undefined
   const isInOptDeps = deps.optionalDependencies[packageName] !== undefined
+  const isInPeerDeps = deps.peerDependencies[packageName] === undefined
 
   if (isInDeps ||
-    (allowDevDeps && isInDevDeps) ||
-    (allowOptDeps && isInOptDeps)
+    (depsOptions.allowDevDeps && isInDevDeps) ||
+    (depsOptions.allowPeerDeps && isInPeerDeps) ||
+    (depsOptions.allowOptDeps && isInOptDeps)
   ) {
     return
   }
 
-  if (isInDevDeps && !allowDevDeps) {
+  if (isInDevDeps && !depsOptions.allowDevDeps) {
     context.report(node, devDepErrorMessage(packageName))
     return
   }
 
-  if (isInOptDeps && !allowOptDeps) {
+  if (isInOptDeps && !depsOptions.allowOptDeps) {
     context.report(node, optDepErrorMessage(packageName))
     return
   }
@@ -70,22 +73,26 @@ function reportIfMissing(context, deps, allowDevDeps, allowOptDeps, node, name)
 
 module.exports = function (context) {
   const options = context.options[0] || {}
-  const allowDevDeps = options.devDependencies !== false
-  const allowOptDeps = options.optionalDependencies !== false
   const deps = getDependencies(context)
 
   if (!deps) {
     return {}
   }
 
+  const depsOptions = {
+    allowDevDeps: options.devDependencies !== false,
+    allowOptDeps: options.optionalDependencies !== false,
+    allowPeerDeps: options.peerDependencies === true,
+  }
+
   // todo: use module visitor from module-utils core
   return {
     ImportDeclaration: function (node) {
-      reportIfMissing(context, deps, allowDevDeps, allowOptDeps, node, node.source.value)
+      reportIfMissing(context, deps, depsOptions, node, node.source.value)
     },
     CallExpression: function handleRequires(node) {
       if (isStaticRequire(node)) {
-        reportIfMissing(context, deps, allowDevDeps, allowOptDeps, node, node.arguments[0].value)
+        reportIfMissing(context, deps, depsOptions, node, node.arguments[0].value)
       }
     },
   }
@@ -97,6 +104,7 @@ module.exports.schema = [
     'properties': {
       'devDependencies': { 'type': 'boolean' },
       'optionalDependencies': { 'type': 'boolean' },
+      'peerDependencies': { 'type': 'boolean' },
     },
     'additionalProperties': false,
   },

tests/src/rules/no-extraneous-dependencies.js

@@ -24,6 +24,11 @@ ruleTester.run('no-extraneous-dependencies', rule, {
     test({ code: 'import "@scope/core"'}),
 
     test({ code: 'import "electron"', settings: { 'import/core-modules': ['electron'] } }),
+    test({
+      code: 'import "eslint"',
+      options: [{peerDependencies: true}],
+      settings: { 'import/resolver': { node: { paths: [ path.join(__dirname, '../../files') ] } } },
+    }),
 
     // 'project' type
     test({
@@ -84,6 +89,14 @@ ruleTester.run('no-extraneous-dependencies', rule, {
         message: '\'eslint\' should be listed in the project\'s dependencies, not devDependencies.',
       }],
     }),
+    test({
+      code: 'var eslint = require("eslint")',
+      options: [{devDependencies: false, peerDependencies: false}],
+      errors: [{
+        ruleId: 'no-extraneous-dependencies',
+        message: '\'eslint\' should be listed in the project\'s dependencies, not devDependencies.',
+      }],
+    }),
     test({
       code: 'var eslint = require("lodash.isarray")',
       options: [{optionalDependencies: false}],