minor refactoring

lib/single-file/css-rules-matcher.js

@@ -24,6 +24,16 @@ this.RulesMatcher = this.RulesMatcher || (() => {
 
 	const MEDIA_ALL = "all";
 	const IGNORED_PSEUDO_CLASSES = [":focus", ":focus-within", ":hover", ":link", ":visited", ":active"];
+	const SELECTOR_TOKEN_TYPE_TAG = "tag";
+	const SELECTOR_TOKEN_TYPE_ATTRIBUTE = "attribute";
+	const SELECTOR_TOKEN_TYPE_PSEUDO = "pseudo";
+	const SELECTOR_TOKEN_TYPE_PSEUDO_ELEMENT = "pseudo-element";
+	const SELECTOR_TOKEN_NAME_ID = "id";
+	const SELECTOR_TOKEN_NAME_CLASS = "class";
+	const SELECTOR_TOKEN_NAME_NOT = "not";
+	const SELECTOR_TOKEN_ACTION_EQUALS = "equals";
+	const SELECTOR_TOKEN_ACTION_ELEMENT = "element";
+	const SELECTOR_TOKEN_VALUE_STAR = "*";
 
 	class RulesMatcher {
 		constructor(doc) {
@@ -61,11 +71,13 @@ this.RulesMatcher = this.RulesMatcher || (() => {
 
 	function getMatchedElementsRules(doc, cssRules, mediaInfo, sheetIndex) {
 		Array.from(cssRules).forEach((cssRule, ruleIndex) => {
-			if (cssRule.type == CSSRule.MEDIA_RULE) {
-				const ruleMediaInfo = createMediaInfo(cssRule.media);
-				mediaInfo.medias.set(cssRule.media, ruleMediaInfo);
+			const cssRuleType = cssRule.type;
+			if (cssRuleType == CSSRule.MEDIA_RULE) {
+				const cssRuleMedia = cssRule.media;
+				const ruleMediaInfo = createMediaInfo(cssRuleMedia);
+				mediaInfo.medias.set(cssRuleMedia, ruleMediaInfo);
 				getMatchedElementsRules(doc, cssRule.cssRules, ruleMediaInfo, sheetIndex);
-			} else if (cssRule.type == CSSRule.STYLE_RULE) {
+			} else if (cssRuleType == CSSRule.STYLE_RULE) {
 				const selectorText = cssRule.selectorText;
 				if (selectorText) {
 					let selectors;
@@ -110,14 +122,12 @@ this.RulesMatcher = this.RulesMatcher || (() => {
 	}
 
 	function getInfo(element, cssRule, selector, mediaInfo, ruleIndex, sheetIndex) {
-		let elementInfo;
-		if (mediaInfo.elements.has(element)) {
-			elementInfo = mediaInfo.elements.get(element);
-		} else {
+		let elementInfo = mediaInfo.elements.get(element);
+		if (!elementInfo) {
 			elementInfo = [];
-			const elementStyle = element.getAttribute("style");
-			if (elementStyle) {
-				elementInfo.push({ cssStyle: element.style });
+			const elementStyle = element.style;
+			if (elementStyle.length) {
+				elementInfo.push({ cssStyle: elementStyle });
 			}
 			mediaInfo.elements.set(element, elementInfo);
 		}
@@ -174,17 +184,18 @@ this.RulesMatcher = this.RulesMatcher || (() => {
 				stylesInfo.forEach(styleInfo => {
 					const important = cssStyle.getPropertyPriority(styleInfo.name);
 					const styleValue = cssStyle.getPropertyValue(styleInfo.name) + (important && "!" + important);
-					elementStylesInfo.set(styleInfo.name, { styleValue, cssStyle: ruleInfo.cssStyle, important });
+					elementStylesInfo.set(styleInfo.name, { styleValue, cssStyle, important });
 				});
 			} else {
-				const cssStyle = ruleInfo.cssRule.style;
+				const cssRule = ruleInfo.cssRule;
+				const cssStyle = cssRule.style;
 				const stylesInfo = parseCss.parseAListOfDeclarations(cssStyle.cssText);
 				stylesInfo.forEach(styleInfo => {
 					const important = cssStyle.getPropertyPriority(styleInfo.name);
 					const styleValue = cssStyle.getPropertyValue(styleInfo.name) + (important && "!" + important);
 					let elementStyleInfo = elementStylesInfo.get(styleInfo.name);
 					if (!elementStyleInfo || (important && !elementStyleInfo.important)) {
-						elementStylesInfo.set(styleInfo.name, { styleValue, cssRule: ruleInfo.cssRule, selectorText: ruleInfo.selectorText, selectorsText: ruleInfo.selectorsText, important });
+						elementStylesInfo.set(styleInfo.name, { styleValue, cssRule, selectorText: ruleInfo.selectorText, selectorsText: ruleInfo.selectorsText, important });
 					}
 				});
 			}
@@ -210,15 +221,15 @@ this.RulesMatcher = this.RulesMatcher || (() => {
 
 	function computeSpecificity(selector, specificity = { a: 0, b: 0, c: 0 }) {
 		selector.forEach(token => {
-			if (token.expandedSelector && token.type == "attribute" && token.name === "id" && token.action === "equals") {
+			if (token.expandedSelector && token.type == SELECTOR_TOKEN_TYPE_ATTRIBUTE && token.name == SELECTOR_TOKEN_NAME_ID && token.action == SELECTOR_TOKEN_ACTION_EQUALS) {
 				specificity.a++;
 			}
-			if ((!token.expandedSelector && token.type == "attribute") ||
-				(token.expandedSelector && token.type == "attribute" && token.name === "class" && token.action === "element") ||
-				(token.type == "pseudo" && token.name != "not")) {
+			if ((!token.expandedSelector && token.type == SELECTOR_TOKEN_TYPE_ATTRIBUTE) ||
+				(token.expandedSelector && token.type == SELECTOR_TOKEN_TYPE_ATTRIBUTE && token.name == SELECTOR_TOKEN_NAME_CLASS && token.action == SELECTOR_TOKEN_ACTION_ELEMENT) ||
+				(token.type == SELECTOR_TOKEN_TYPE_PSEUDO && token.name != SELECTOR_TOKEN_NAME_NOT)) {
 				specificity.b++;
 			}
-			if ((token.type == "tag" && token.value != "*") || (token.type == "pseudo-element")) {
+			if ((token.type == SELECTOR_TOKEN_TYPE_TAG && token.value != SELECTOR_TOKEN_VALUE_STAR) || (token.type == SELECTOR_TOKEN_TYPE_PSEUDO_ELEMENT)) {
 				specificity.c++;
 			}
 			if (token.data) {