Add plugin functionality

Author: BrainMaestro

lib/index.js

@@ -0,0 +1,18 @@
+/**
+ * @fileoverview Optimize regex literals
+ * @author Ezinwa Okpoechi
+ */
+"use strict";
+
+//------------------------------------------------------------------------------
+// Requirements
+//------------------------------------------------------------------------------
+
+var requireIndex = require("requireindex");
+
+//------------------------------------------------------------------------------
+// Plugin Definition
+//------------------------------------------------------------------------------
+
+// import all rules in lib/rules
+module.exports.rules = requireIndex(__dirname + "/rules");

lib/rules/optimize-regex.js

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+/**
+ * @fileoverview Optimize regex literals
+ * @author Ezinwa Okpoechi
+ */
+
+'use strict';
+
+const { optimize } = require('regexp-tree');
+
+//------------------------------------------------------------------------------
+// Rule Definition
+//------------------------------------------------------------------------------
+
+module.exports = {
+  meta: {
+    docs: {
+      description: 'Optimize regex literals',
+      category: 'Fill me in',
+      recommended: true,
+    },
+    fixable: 'code',
+    schema: [],
+  },
+
+  create: function(context) {
+    const sourceCode = context.getSourceCode();
+
+    /**
+     * Validate regular expression literals
+     * @param {ASTNode} node node to validate
+     * @returns {void}
+     * @private
+     */
+
+    function checkLiteral(node) {
+      const { type, value, start } = sourceCode.getFirstToken(node);
+
+      if (type !== 'RegularExpression') {
+        return;
+      }
+
+      const optimizedRegex = optimize(value).toRegExp();
+
+      if (value === optimizedRegex.toString()) {
+        return;
+      }
+
+      context.report({
+        node,
+        message: '{{original}} can be optimized to {{optimized}}',
+        data: {
+          original: value,
+          optimized: optimizedRegex,
+        },
+        fix(fixer) {
+          return fixer.replaceText(node, optimizedRegex.toString());
+        },
+      });
+    }
+
+    return {
+      Literal: checkLiteral,
+    };
+  },
+};

tests/lib/rules/optimize-regex.js

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+/**
+ * @fileoverview Optimize regex literals
+ * @author Ezinwa Okpoechi
+ */
+
+'use strict';
+
+//------------------------------------------------------------------------------
+// Requirements
+//------------------------------------------------------------------------------
+
+var rule = require('../../../lib/rules/optimize-regex'),
+  RuleTester = require('eslint').RuleTester;
+
+var ruleTester = new RuleTester();
+ruleTester.run('optimize-regex', rule, {
+  valid: ['var foo = /foo/i'],
+
+  invalid: [
+    {
+      code: 'var re = /[a-zA-Z_0-9][A-Z_\\da-z]*\\e{1,}/',
+      output: 'var re = /\\w+e+/',
+      errors: [
+        {
+          message: '/[a-zA-Z_0-9][A-Z_\\da-z]*\\e{1,}/ can be optimized to /\\w+e+/',
+          type: 'Literal',
+        },
+      ],
+    },
+  ],
+});