fix inefficient .enable() regex and .enabled() test

Qix- · Qix- · commit d2d6bf0bab3a · 2024-12-06T13:27:40.000+01:00
diff --git a/package.json b/package.json
@@ -56,5 +56,10 @@
   "browser": "./src/browser.js",
   "engines": {
     "node": ">=6.0"
+  },
+  "xo": {
+    "rules": {
+      "import/extensions": "off"
+    }
   }
 }
diff --git a/src/browser.js b/src/browser.js
@@ -129,6 +129,7 @@ function useColors() {
 
 	// Is webkit? http://stackoverflow.com/a/16459606/376773
 	// document is undefined in react-native: https://github.com/facebook/react-native/pull/1632
+	// eslint-disable-next-line no-return-assign
 	return (typeof document !== 'undefined' && document.documentElement && document.documentElement.style && document.documentElement.style.WebkitAppearance) ||
 		// Is firebug? http://stackoverflow.com/a/398120/376773
 		(typeof window !== 'undefined' && window.console && (window.console.firebug || (window.console.exception && window.console.table))) ||
diff --git a/src/common.js b/src/common.js
@@ -166,24 +166,62 @@ function setup(env) {
 		createDebug.names = [];
 		createDebug.skips = [];
 
-		let i;
-		const split = (typeof namespaces === 'string' ? namespaces : '').split(/[\s,]+/);
-		const len = split.length;
-
-		for (i = 0; i < len; i++) {
-			if (!split[i]) {
-				// ignore empty strings
-				continue;
+		const split = (typeof namespaces === 'string' ? namespaces : '')
+			.trim()
+			.replace(' ', ',')
+			.split(',')
+			.filter(Boolean);
+
+		for (const ns of split) {
+			if (ns[0] === '-') {
+				createDebug.skips.push(ns.slice(1));
+			} else {
+				createDebug.names.push(ns);
 			}
+		}
+	}
 
-			namespaces = split[i].replace(/\*/g, '.*?');
-
-			if (namespaces[0] === '-') {
-				createDebug.skips.push(new RegExp('^' + namespaces.slice(1) + '$'));
+	/**
+	 * Checks if the given string matches a namespace template, honoring
+	 * asterisks as wildcards.
+	 *
+	 * @param {String} search
+	 * @param {String} template
+	 * @return {Boolean}
+	 */
+	function matchesTemplate(search, template) {
+		let searchIndex = 0;
+		let templateIndex = 0;
+		let starIndex = -1;
+		let matchIndex = 0;
+
+		while (searchIndex < search.length) {
+			if (templateIndex < template.length && (template[templateIndex] === search[searchIndex] || template[templateIndex] === '*')) {
+				// Match character or proceed with wildcard
+				if (template[templateIndex] === '*') {
+					starIndex = templateIndex;
+					matchIndex = searchIndex;
+					templateIndex++; // Skip the '*'
+				} else {
+					searchIndex++;
+					templateIndex++;
+				}
+			} else if (starIndex !== -1) { // eslint-disable-line no-negated-condition
+				// Backtrack to the last '*' and try to match more characters
+				templateIndex = starIndex + 1;
+				matchIndex++;
+				searchIndex = matchIndex;
 			} else {
-				createDebug.names.push(new RegExp('^' + namespaces + '$'));
+				return false; // No match
 			}
 		}
+
+		// Handle trailing '*' in template
+		while (templateIndex < template.length && template[templateIndex] === '*') {
+			templateIndex++;
+		}
+
+		return templateIndex === template.length;
 	}
 
 	/**
@@ -194,8 +232,8 @@ function setup(env) {
 	*/
 	function disable() {
 		const namespaces = [
-			...createDebug.names.map(toNamespace),
-			...createDebug.skips.map(toNamespace).map(namespace => '-' + namespace)
+			...createDebug.names,
+			...createDebug.skips.map(namespace => '-' + namespace)
 		].join(',');
 		createDebug.enable('');
 		return namespaces;
@@ -209,41 +247,21 @@ function setup(env) {
 	* @api public
 	*/
 	function enabled(name) {
-		if (name[name.length - 1] === '*') {
-			return true;
-		}
-
-		let i;
-		let len;
-
-		for (i = 0, len = createDebug.skips.length; i < len; i++) {
-			if (createDebug.skips[i].test(name)) {
+		for (const skip of createDebug.skips) {
+			if (matchesTemplate(name, skip)) {
 				return false;
 			}
 		}
 
-		for (i = 0, len = createDebug.names.length; i < len; i++) {
-			if (createDebug.names[i].test(name)) {
+		for (const ns of createDebug.names) {
+			if (matchesTemplate(name, ns)) {
 				return true;
 			}
 		}
 
 		return false;
 	}
 
-	/**
-	* Convert regexp to namespace
-	*
-	* @param {RegExp} regxep
-	* @return {String} namespace
-	* @api private
-	*/
-	function toNamespace(regexp) {
-		return regexp.toString()
-			.substring(2, regexp.toString().length - 2)
-			.replace(/\.\*\?$/, '*');
-	}
-
 	/**
 	* Coerce `val`.
 	*

Original file line number	Diff line number	Diff line change
`@@ -56,5 +56,10 @@`
`56`	`56`	`"browser": "./src/browser.js",`
`57`	`57`	`"engines": {`
`58`	`58`	`"node": ">=6.0"`
	`59`	`+ },`
	`60`	`+ "xo": {`
	`61`	`+ "rules": {`
	`62`	`+ "import/extensions": "off"`
	`63`	`+ }`
`59`	`64`	`}`
`60`	`65`	`}`