extracted const array from serializeTextNode

lib/single-file/serializer.js

@@ -50,6 +50,7 @@ this.serializer = this.serializer || (() => {
 		{ tagName: "td", accept: next => !next || ["TD", "TH"].includes(next.tagName) },
 		{ tagName: "th", accept: next => !next || ["TD", "TH"].includes(next.tagName) }
 	];
+	const TEXT_NODE_TAGS = ["style", "script", "xmp", "iframe", "noembed", "noframes", "plaintext", "noscript"];
 
 	return {
 		process(doc, compressHTML) {
@@ -91,7 +92,7 @@ this.serializer = this.serializer || (() => {
 		if (parentNode && parentNode.nodeType == Node.ELEMENT_NODE) {
 			parentTagName = parentNode.tagName.toLowerCase();
 		}
-		if (!parentTagName || ["style", "script", "xmp", "iframe", "noembed", "noframes", "plaintext", "noscript"].includes(parentTagName)) {
+		if (!parentTagName || TEXT_NODE_TAGS.includes(parentTagName)) {
 			return textNode.textContent;
 		} else {
 			return textNode.textContent.replace(/&/g, "&amp;").replace(/\u00a0/g, "&nbsp;").replace(/</g, "&lt;").replace(/</g, "&gt;");