[New] max-dependencies: add option ignoreTypeImports

Author: rfermann

CHANGELOG.md

@@ -10,6 +10,7 @@ This change log adheres to standards from [Keep a CHANGELOG](http://keepachangel
 - [`no-dynamic-require`]: add option `esmodule` ([#1223], thanks [@vikr01])
 - [`named`]: add `commonjs` option ([#1222], thanks [@vikr01])
 - [`no-namespace`]: Add `ignore` option ([#2112], thanks [@aberezkin])
+- [`max-dependencies`]: add option `ignoreTypeImports` ([#1847], thanks [@rfermann])
 
 ### Fixed
 - [`no-duplicates`]: ensure autofix avoids excessive newlines ([#2028], thanks [@ertrzyiks])
@@ -853,6 +854,7 @@ for info on changes for earlier releases.
 [#1878]: https://github.com/benmosher/eslint-plugin-import/pull/1878
 [#1860]: https://github.com/benmosher/eslint-plugin-import/pull/1860
 [#1848]: https://github.com/benmosher/eslint-plugin-import/pull/1848
+[#1847]: https://github.com/benmosher/eslint-plugin-import/pull/1847
 [#1846]: https://github.com/benmosher/eslint-plugin-import/pull/1846
 [#1836]: https://github.com/benmosher/eslint-plugin-import/pull/1836
 [#1835]: https://github.com/benmosher/eslint-plugin-import/pull/1835

src/rules/max-dependencies.js

@@ -2,15 +2,14 @@ import moduleVisitor from 'eslint-module-utils/moduleVisitor';
 import docsUrl from '../docsUrl';
 
 const DEFAULT_MAX = 10;
+const DEFAULT_IGNORE_TYPE_IMPORTS = false;
+const TYPE_IMPORT = 'type';
 
 const countDependencies = (dependencies, lastNode, context) => {
   const { max } = context.options[0] || { max: DEFAULT_MAX };
 
   if (dependencies.size > max) {
-    context.report(
-      lastNode,
-      `Maximum number of dependencies (${max}) exceeded.`
-    );
+    context.report(lastNode, `Maximum number of dependencies (${max}) exceeded.`);
   }
 };
 
@@ -26,22 +25,29 @@ module.exports = {
         'type': 'object',
         'properties': {
           'max': { 'type': 'number' },
+          'ignoreTypeImports': { 'type': 'boolean' },
         },
         'additionalProperties': false,
       },
     ],
   },
 
   create: context => {
+    const {
+      ignoreTypeImports = DEFAULT_IGNORE_TYPE_IMPORTS,
+    } = context.options[0] || {};
+
     const dependencies = new Set(); // keep track of dependencies
     let lastNode; // keep track of the last node to report on
 
     return Object.assign({
       'Program:exit': function () {
         countDependencies(dependencies, lastNode, context);
       },
-    }, moduleVisitor((source) => {
-      dependencies.add(source.value);
+    }, moduleVisitor((source, { importKind }) => {
+      if (importKind !== TYPE_IMPORT || !ignoreTypeImports) {
+        dependencies.add(source.value);
+      }
       lastNode = source;
     }, { commonjs: true }));
   },

tests/src/rules/max-dependencies.js

@@ -1,6 +1,8 @@
-import { test } from '../utils';
+import { test, getTSParsers } from '../utils';
 
 import { RuleTester } from 'eslint';
+import eslintPkg from 'eslint/package.json';
+import semver from 'semver';
 
 const ruleTester = new RuleTester();
 const rule = require('rules/max-dependencies');
@@ -74,5 +76,58 @@ ruleTester.run('max-dependencies', rule, {
         'Maximum number of dependencies (1) exceeded.',
       ],
     }),
+
+    test({
+      code: 'import type { x } from \'./foo\'; import type { y } from \'./bar\'; import type { z } from \'./baz\'',
+      parser: require.resolve('babel-eslint'),
+      options: [{
+        max: 2,
+        ignoreTypeImports: false,
+      }],
+      errors: [
+        'Maximum number of dependencies (2) exceeded.',
+      ],
+    }),
   ],
 });
+
+context('TypeScript', { skip: semver.satisfies(eslintPkg.version, '>5.0.0') }, () => {
+  getTSParsers().forEach((parser) => {
+    ruleTester.run(`max-dependencies (${parser.replace(process.cwd(), '.')})`, rule, {
+      valid: [    
+        test({
+          code: 'import type { x } from \'./foo\'; import { y } from \'./bar\';',
+          parser: parser,
+          options: [{
+            max: 1,
+            ignoreTypeImports: true,
+          }],
+        }),
+      ],
+      invalid: [    
+        test({
+          code: 'import type { x } from \'./foo\'; import type { y } from \'./bar\'',
+          parser: parser,
+          options: [{
+            max: 1,
+          }],
+          errors: [
+            'Maximum number of dependencies (1) exceeded.',
+          ],
+        }),
+    
+        test({
+          code: 'import type { x } from \'./foo\'; import type { y } from \'./bar\'; import type { z } from \'./baz\'',
+          parser: parser,
+          options: [{
+            max: 2,
+            ignoreTypeImports: false,
+          }],
+          errors: [
+            'Maximum number of dependencies (2) exceeded.',
+          ],
+        }),
+      ],
+    });
+  });
+});