Inline regex performs persistently faster. Less code.

Author: gnat

script.js

@@ -1,7 +1,6 @@
 // 🌘 CSS Scope Inline (https://github.com/gnat/css-scope-inline)
 window.cssScopeCount ??= 1 // Let extra copies share the scope count.
-new MutationObserver((mutations, observer) => {
-	var cssScopePattern = new RegExp('\.(me|this|self)(?![A-Za-z0-9\_\-])', 'g') // Can use: .me .this .self
+new MutationObserver(mutations => {
 	for (var mutation of mutations) {
 		if (mutation.type !== "childList") continue // Skip if not mutating nodes.
 		var nodes = [...mutation.addedNodes] // Get new nodes.
@@ -12,7 +11,7 @@ new MutationObserver((mutations, observer) => {
 			if (node.textContent.includes('.self__')) continue // Skip if already processed.
 			var scope = 'self__'+(window.cssScopeCount++) // Ready. Make unique scope, example: .self__1234
 			node.parentNode.classList.add(scope)
-			node.textContent = node.textContent.replace(cssScopePattern, '.'+scope)
+			node.textContent = node.textContent.replace(/\.(me|this|self)(?![A-Za-z0-9\_\-])/g, '.'+scope) // Can use: .me .this .self
 		}
 	}
 }).observe(document.documentElement, {childList: true, subtree: true})