Added feature to allow <style> in messages

dev/Common/CSS.js

@@ -0,0 +1,82 @@
+
+export class CSS
+{
+	/*
+		Parses given css string, and returns css object
+		keys as selectors and values are css rules
+		eliminates all css comments before parsing
+
+		@param source css string to be parsed
+
+		@return object css
+	*/
+	parse(source) {
+
+		const css = [];
+
+		css.toString = () => css.reduce(
+			(ret, tmp) =>
+				ret + tmp.selector + ' {\n'
+					+ (tmp.type === 'media' ? tmp.subStyles.toString() : tmp.rules)
+					+ '}\n'
+			,
+			''
+		);
+
+		/**
+		 * Given css array, parses it and then for every selector,
+		 * prepends namespace to prevent css collision issues
+		 */
+		css.applyNamespace = (namespace) => css.forEach(obj => {
+			if (obj.type === 'media') {
+				obj.subStyles.applyNamespace(namespace);
+			} else {
+				obj.selector = obj.selector.split(',').map(selector => namespace + ' ' + selector).join(',');
+			}
+		});
+
+		if (source) {
+			source = source
+				// strip comments
+				.replace(/\/\*[\s\S]*?\*\/|<!--|-->/gi, '')
+				// strip import statements
+				.replace(/@import .*?;/gi , '')
+				// strip keyframe statements
+				.replace(/((@.*?keyframes [\s\S]*?){([\s\S]*?}\s*?)})/gi, '');
+
+			// unified regex to match css & media queries together
+			let unified = /((\s*?(?:\/\*[\s\S]*?\*\/)?\s*?@media[\s\S]*?){([\s\S]*?)}\s*?})|(([\s\S]*?){([\s\S]*?)})/gi,
+				arr;
+
+			while (true) {
+				arr = unified.exec(source);
+				if (arr === null) {
+					break;
+				}
+
+				let selector = arr[arr[2] === undefined ? 5 : 2].split('\r\n').join('\n').trim()
+					// Never have more than a single line break in a row
+					.replace(/\n+/, "\n");
+
+				// determine the type
+				if (selector.includes('@media')) {
+					// we have a media query
+					css.push({
+						selector: selector,
+						type: 'media',
+						subStyles: this.parse(arr[3] + '\n}') //recursively parse media query inner css
+					});
+				} else if (!selector.includes('@') && ![':root','html','body'].includes(selector)) {
+					// we have standard css
+					css.push({
+						selector: selector,
+						rules: arr[6]
+					});
+				}
+			}
+		}
+
+		return css;
+	}
+
+}