Merge pull request #117 from scothis/require-ext

Add require-extension rule

Author: yannickcr

docs/rules/require-extenion.md

@@ -0,0 +1,38 @@
+# Restrict file extensions that may be required (require-extension)
+
+`require()` statements should generally not include a file extension as there is a well defined mechanism for resolving a module ID to a specific file. This rule inspects the module ID being required and creates a warning if the ID contains a '.jsx' file extension.
+
+Note: this rule does not prevent required files from containing these extensions, it merely prevents the extension from being included in the `require()` statement.
+
+## Rule Details
+
+The following patterns are considered warnings:
+
+```js
+var index = require('./index.jsx');
+
+// When [1, {extensions: ['.js']}]
+var index = require('./index.js');
+```
+
+The following patterns are not considered warnings:
+
+```js
+var index = require('./index');
+
+var eslint = require('eslint');
+```
+
+## Rule Options
+
+The set of forbidden extensions is configurable. By default '.jsx' is blocked. If you wanted to forbid both '.jsx' and '.js', the configuration would be:
+
+```js
+"rules": {
+  "react/require-extension": [1, { "extensions": [".js", ".jsx"] }],
+}
+```
+
+## When Not To Use It
+
+If you have file in your project with a '.jsx' file extension and do not have `require()` configured to automatically resolve '.jsx' files.

index.js

@@ -18,7 +18,8 @@ module.exports = {
     'jsx-sort-props': require('./lib/rules/jsx-sort-props'),
     'jsx-sort-prop-types': require('./lib/rules/jsx-sort-prop-types'),
     'jsx-boolean-value': require('./lib/rules/jsx-boolean-value'),
-    'sort-comp': require('./lib/rules/sort-comp')
+    'sort-comp': require('./lib/rules/sort-comp'),
+    'require-extension': require('./lib/rules/require-extension')
   },
   rulesConfig: {
     'jsx-uses-react': 0,
@@ -37,6 +38,7 @@ module.exports = {
     'jsx-sort-props': 0,
     'jsx-sort-prop-types': 0,
     'jsx-boolean-value': 0,
-    'sort-comp': 0
+    'sort-comp': 0,
+    'require-extension': 0
   }
 };

lib/rules/require-extension.js

@@ -0,0 +1,72 @@
+/**
+ * @fileoverview Restrict file extensions that may be required
+ * @author Scott Andrews
+ */
+'use strict';
+
+var path = require('path');
+
+// ------------------------------------------------------------------------------
+// Constants
+// ------------------------------------------------------------------------------
+
+var DEFAULTS = {
+  extentions: ['.jsx']
+};
+
+// ------------------------------------------------------------------------------
+// Rule Definition
+// ------------------------------------------------------------------------------
+
+module.exports = function(context) {
+
+  function isRequire(expression) {
+    return expression.callee.name === 'require';
+  }
+
+  function getId(expression) {
+    return expression.arguments[0] && expression.arguments[0].value;
+  }
+
+  function getExtension(id) {
+    return path.extname(id || '');
+  }
+
+  function getExtentionsConfig() {
+    return context.options[0] && context.options[0].extensions || DEFAULTS.extentions;
+  }
+
+  var forbiddenExtensions = getExtentionsConfig().reduce(function (extensions, extension) {
+    extensions[extension] = true;
+    return extensions;
+  }, Object.create(null));
+
+  function isForbiddenExtension(ext) {
+    return ext in forbiddenExtensions;
+  }
+
+  // --------------------------------------------------------------------------
+  // Public
+  // --------------------------------------------------------------------------
+
+  return {
+
+    CallExpression: function(node) {
+      if (isRequire(node)) {
+        var ext = getExtension(getId(node));
+        if (isForbiddenExtension(ext)) {
+          context.report(node, 'Unable to require module with extension \'' + ext + '\'');
+        }
+      }
+    }
+
+  };
+
+};
+
+module.exports.schema = [{
+  type: 'object',
+  properties: {
+    extensions: {type: 'array'}
+  }
+}];

tests/lib/rules/require-extension.js

@@ -0,0 +1,95 @@
+/**
+ * @fileoverview Restrict file extensions that may be required
+ * @author Scott Andrews
+ */
+'use strict';
+
+// ------------------------------------------------------------------------------
+// Requirements
+// ------------------------------------------------------------------------------
+
+var eslint = require('eslint').linter;
+var ESLintTester = require('eslint-tester');
+
+// ------------------------------------------------------------------------------
+// Code Snippets
+// ------------------------------------------------------------------------------
+
+var REQUIRE_PACKAGE = 'require(\'eslint\')';
+
+var REQUIRE_JS = 'require(\'./index.js\')';
+
+var REQUIRE_JSX = 'require(\'./index.jsx\')';
+
+var REQUIRE_JSON = 'require(\'./index.json\')';
+
+var REQUIRE_EMPTY = 'require()';
+
+var REQUIRE_OBJECT = 'require({})';
+
+// ------------------------------------------------------------------------------
+// Tests
+// ------------------------------------------------------------------------------
+
+var eslintTester = new ESLintTester(eslint);
+eslintTester.addRuleTest('lib/rules/require-extension', {
+
+    valid: [
+        {
+            code: REQUIRE_PACKAGE
+        }, {
+            code: REQUIRE_JS
+        }, {
+            code: REQUIRE_JSON
+        }, {
+            code: REQUIRE_EMPTY
+        }, {
+            code: REQUIRE_OBJECT
+        }, {
+            code: REQUIRE_PACKAGE,
+            args: [1]
+        }, {
+            code: REQUIRE_JS,
+            args: [1]
+        }, {
+            code: REQUIRE_JSON,
+            args: [1]
+        }, {
+            code: REQUIRE_EMPTY,
+            args: [1]
+        }, {
+            code: REQUIRE_OBJECT,
+            args: [1]
+        }, {
+            code: REQUIRE_JSON,
+            args: [1, {extensions: ['.js']}]
+        }, {
+            code: REQUIRE_JSX,
+            args: [1, {extensions: ['.js']}]
+        }
+    ],
+
+    invalid: [
+        {
+            code: REQUIRE_JSX,
+            errors: [{message: 'Unable to require module with extension \'.jsx\''}]
+        }, {
+            code: REQUIRE_JSX,
+            args: [1],
+            errors: [{message: 'Unable to require module with extension \'.jsx\''}]
+        }, {
+            code: REQUIRE_JS,
+            args: [1, {extensions: ['.js']}],
+            errors: [{message: 'Unable to require module with extension \'.js\''}]
+        }, {
+            code: REQUIRE_JS,
+            args: [1, {extensions: ['.js', '.jsx']}],
+            errors: [{message: 'Unable to require module with extension \'.js\''}]
+        }, {
+            code: REQUIRE_JSX,
+            args: [1, {extensions: ['.js', '.jsx']}],
+            errors: [{message: 'Unable to require module with extension \'.jsx\''}]
+        }
+    ]
+
+});