[New] no-extraneous-dependencies: added includeTypes option to validate type imports

Fixes import-js#2542

Author: bdwain

CHANGELOG.md

@@ -13,6 +13,7 @@ This change log adheres to standards from [Keep a CHANGELOG](https://keepachange
 - [`no-anonymous-default-export`]: add `allowNew` option ([#2505], thanks [@DamienCassou])
 - [`order`]: Add `distinctGroup` option ([#2395], thanks [@hyperupcall])
 - [`no-extraneous-dependencies`]: Add `includeInternal` option ([#2541], thanks [@bdwain])
+- [`no-extraneous-dependencies`]: Add `includeTypes` option ([#2543], thanks [@bdwain])
 
 ### Fixed
 - [`order`]: move nested imports closer to main import entry ([#2396], thanks [@pri1311])

docs/rules/no-extraneous-dependencies.md

@@ -1,7 +1,7 @@
 # import/no-extraneous-dependencies: Forbid the use of extraneous packages
 
 Forbid the import of external modules that are not declared in the `package.json`'s `dependencies`, `devDependencies`, `optionalDependencies`, `peerDependencies`, or `bundledDependencies`.
-The closest parent `package.json` will be used. If no `package.json` is found, the rule will not lint anything. This behavior can be changed with the rule option `packageDir`. Normally ignores imports of modules marked internal, but this can be changed with the rule option `includeInternal`.
+The closest parent `package.json` will be used. If no `package.json` is found, the rule will not lint anything. This behavior can be changed with the rule option `packageDir`. Normally ignores imports of modules marked internal, but this can be changed with the rule option `includeInternal`. Type imports can be verified by specifying `includeTypes`.
 
 Modules have to be installed for this rule to work.
 
@@ -31,10 +31,10 @@ You can also use an array of globs instead of literal booleans:
 
 When using an array of globs, the setting will be set to `true` (no errors reported) if the name of the file being linted matches a single glob in the array, and `false` otherwise.
 
-There is a boolean option called `includeInternal`, which enables the checking of internal modules, which are otherwise ignored by this rule.
+There are 2 boolean options to opt into checking extra imports that are normally ignored: `includeInternal`, which enables the checking of internal modules, and `includeTypes`, which enables checking of type imports in TypeScript.
 
 ```js
-"import/no-extraneous-dependencies": ["error", {"includeInternal": true}]
+"import/no-extraneous-dependencies": ["error", {"includeInternal": true, "includeTypes": true}]
 ```
 
 Also there is one more option called `packageDir`, this option is to specify the path to the folder containing package.json.
@@ -109,6 +109,9 @@ var foo = require('"@generated/foo"');
 /* eslint import/no-extraneous-dependencies: ["error", {"includeInternal": true}] */
 import foo from './foo';
 var foo = require('./foo');
+
+/* eslint import/no-extraneous-dependencies: ["error", {"includeTypes": true}] */
+import type { MyType } from 'foo';
 ```
 
 
@@ -123,6 +126,7 @@ import test from 'ava';
 import find from 'lodash.find';
 import isArray from 'lodash.isarray';
 import foo from '"@generated/foo"';
+import type { MyType } from 'foo';
 
 /* eslint import/no-extraneous-dependencies: ["error", {"peerDependencies": true}] */
 import react from 'react';

src/rules/no-extraneous-dependencies.js

@@ -175,10 +175,10 @@ function checkDependencyDeclaration(deps, packageName, declarationStatus) {
 }
 
 function reportIfMissing(context, deps, depsOptions, node, name) {
-  // Do not report when importing types
+  // Do not report when importing types unless option is enabled
   if (
-    node.importKind === 'type' ||
-    node.importKind === 'typeof'
+    !depsOptions.verifyTypeImports &&
+    (node.importKind === 'type' || node.importKind === 'typeof')
   ) {
     return;
   }
@@ -267,6 +267,7 @@ module.exports = {
           'bundledDependencies': { 'type': ['boolean', 'array'] },
           'packageDir': { 'type': ['string', 'array'] },
           'includeInternal': { 'type': ['boolean'] },
+          'includeTypes': { 'type': ['boolean'] },
         },
         'additionalProperties': false,
       },
@@ -284,6 +285,7 @@ module.exports = {
       allowPeerDeps: testConfig(options.peerDependencies, filename) !== false,
       allowBundledDeps: testConfig(options.bundledDependencies, filename) !== false,
       verifyInternalDeps: !!options.includeInternal,
+      verifyTypeImports: !!options.includeTypes,
     };
 
     return moduleVisitor((source, node) => {

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

@@ -435,6 +435,18 @@ describe('TypeScript', () => {
               message: "'a' should be listed in the project's dependencies, not devDependencies.",
             }],
           }, parserConfig)),
+
+          test(Object.assign({
+            code: 'import type T from "a";',
+            options: [{ 
+              packageDir: packageDirWithTypescriptDevDependencies,
+              devDependencies: false,
+              includeTypes: true,
+            }],
+            errors: [{
+              message: "'a' should be listed in the project's dependencies, not devDependencies.",
+            }],
+          }, parserConfig)),
         ],
       });
     });
@@ -454,5 +466,14 @@ typescriptRuleTester.run('no-extraneous-dependencies typescript type imports', r
     }),
   ],
   invalid: [
+    test({
+      code: 'import type { MyType } from "not-a-dependency";',
+      options: [{ includeTypes: true }],
+      filename: testFilePath('./no-unused-modules/typescript/file-ts-a.ts'),
+      parser: parsers.BABEL_OLD,
+      errors: [{
+        message: `'not-a-dependency' should be listed in the project's dependencies. Run 'npm i -S not-a-dependency' to add it`,
+      }],
+    }),
   ],
 });