Add no-namespace rule

CHANGELOG.md

@@ -6,6 +6,7 @@ This change log adheres to standards from [Keep a CHANGELOG](http://keepachangel
 ## [Unreleased]
 ### Added
 - report resolver errors at the top of the linted file
+- add `no-namespace` rule
 
 ## [1.4.0] - 2016-03-25
 ### Added

README.md

@@ -35,11 +35,13 @@ Style guide:
 * Report AMD `require` and `define` calls. ([`no-amd`])
 * Ensure all imports appear before other statements ([`imports-first`])
 * Report repeated import of the same module in multiple places ([`no-duplicates`])
+* Report namespace imports ([`no-namespace`])
 
 [`no-commonjs`]: ./docs/rules/no-commonjs.md
 [`no-amd`]: ./docs/rules/no-amd.md
 [`imports-first`]: ./docs/rules/imports-first.md
 [`no-duplicates`]: ./docs/rules/no-duplicates.md
+[`no-namespace`]: ./docs/rules/no-namespace.md
 
 Work in progress:
 

docs/rules/no-namespace.md

@@ -0,0 +1,24 @@
+# no-namespace
+
+Reports if namespace import is used.
+
+## Rule Details
+
+Valid:
+
+```js
+import defaultExport from './foo'
+import { a, b }  from './bar'
+import defaultExport, { a, b }  from './foobar'
+```
+
+...whereas here imports will be reported:
+
+```js
+import * as foo from 'foo';
+import defaultExport, * as foo from 'foo';
+```
+
+## When Not To Use It
+
+If you want to use namespaces, you don't want to use this rule.

src/index.js

@@ -3,6 +3,7 @@ export const rules = {
   'named': require('./rules/named'),
   'default': require('./rules/default'),
   'namespace': require('./rules/namespace'),
+  'no-namespace': require('./rules/no-namespace'),
   'export': require('./rules/export'),
 
   'no-named-as-default': require('./rules/no-named-as-default'),

src/rules/no-namespace.js

@@ -0,0 +1,17 @@
+/**
+ * @fileoverview Rule to disallow namespace import
+ * @author Radek Benkel
+ */
+
+//------------------------------------------------------------------------------
+// Rule Definition
+//------------------------------------------------------------------------------
+
+
+module.exports = function (context) {
+  return {
+    'ImportNamespaceSpecifier': function (node) {
+      context.report(node, `Unexpected namespace import.`)
+    },
+  }
+}

tests/src/rules/no-namespace.js

@@ -0,0 +1,44 @@
+import { RuleTester } from 'eslint'
+
+const ERROR_MESSAGE = 'Unexpected namespace import.';
+
+const ruleTester = new RuleTester()
+
+ruleTester.run('no-namespace', require('rules/no-namespace'), {
+  valid: [
+    { code: "import { a, b } from 'foo';", parserOptions: { sourceType: 'module' } },
+    { code: "import { a, b } from './foo';", parserOptions: { sourceType: 'module' } },
+    { code: "import bar from 'bar';", parserOptions: { sourceType: 'module' } },
+    { code: "import bar from './bar';", parserOptions: { sourceType: 'module' } }
+  ],
+
+  invalid: [
+    {
+      code: "import * as foo from 'foo';",
+      errors: [ {
+        line: 1,
+        column: 8,
+        message: ERROR_MESSAGE
+      } ],
+      parserOptions: { sourceType: 'module' }
+    },
+    {
+      code: "import defaultExport, * as foo from 'foo';",
+      errors: [ {
+        line: 1,
+        column: 23,
+        message: ERROR_MESSAGE
+      } ],
+      parserOptions: { sourceType: 'module' }
+    },
+    {
+      code: "import * as foo from './foo';",
+      errors: [ {
+        line: 1,
+        column: 8,
+        message: ERROR_MESSAGE
+      } ],
+      parserOptions: { sourceType: 'module' }
+    }
+  ]
+});