use a generic parameter name

lib/single-file/modules/css-fonts-alt-minifier.js

@@ -53,8 +53,8 @@ this.fontsAltMinifier = this.fontsAltMinifier || (() => {
 	let cssTree;
 
 	return {
-		getInstance(cssTreeImpl) {
-			cssTree = cssTreeImpl;
+		getInstance(...args) {
+			[cssTree] = args;
 			return {
 				process: (doc, stylesheets) => {
 					const fontsDetails = {

lib/single-file/modules/css-fonts-minifier.js

@@ -34,10 +34,8 @@ this.fontsMinifier = this.fontsMinifier || (() => {
 	let cssTree, fontPropertyParser, docHelper;
 
 	return {
-		getInstance(cssTreeImpl, fontPropertyParserImpl, docHelperImpl) {
-			cssTree = cssTreeImpl;
-			fontPropertyParser = fontPropertyParserImpl;
-			docHelper = docHelperImpl;
+		getInstance(...args) {
+			[cssTree, fontPropertyParser, docHelper] = args;
 			return {
 				process: (doc, stylesheets, styles, options) => {
 					const stats = { rules: { processed: 0, discarded: 0 }, fonts: { processed: 0, discarded: 0 } };

lib/single-file/modules/css-matched-rules.js

@@ -72,8 +72,8 @@ this.matchedRules = this.matchedRules || (() => {
 	}
 
 	return {
-		getInstance(cssTreeImpl) {
-			cssTree = cssTreeImpl;
+		getInstance(...args) {
+			[cssTree] = args;
 			return {
 				getMediaAllInfo(doc, stylesheets, styles) {
 					return new MatchedRules(doc, stylesheets, styles).getMediaAllInfo();

lib/single-file/modules/css-medias-alt-minifier.js

@@ -26,9 +26,8 @@ this.mediasAltMinifier = this.mediasAltMinifier || (() => {
 	let cssTree, mediaQueryParser;
 
 	return {
-		getInstance(cssTreeImpl, mediaQueryParserImpl) {
-			cssTree = cssTreeImpl;
-			mediaQueryParser = mediaQueryParserImpl;
+		getInstance(...args) {
+			[cssTree, mediaQueryParser] = args;
 			return {
 				process: stylesheets => {
 					const stats = { processed: 0, discarded: 0 };

lib/single-file/modules/css-rules-minifier.js

@@ -25,8 +25,8 @@ this.cssRulesMinifier = this.cssRulesMinifier || (() => {
 	let cssTree;
 
 	return {
-		getInstance(cssTreeImpl) {
-			cssTree = cssTreeImpl;
+		getInstance(...args) {
+			[cssTree] = args;
 			return {
 				process: (stylesheets, styles, mediaAllInfo) => {
 					const stats = { processed: 0, discarded: 0 };

lib/single-file/modules/html-images-alt-minifier.js

@@ -25,8 +25,8 @@ this.imagesAltMinifier = this.imagesAltMinifier || (() => {
 	let srcsetParser;
 
 	return {
-		getInstance(srcsetParserImpl) {
-			srcsetParser = srcsetParserImpl;
+		getInstance(...args) {
+			[srcsetParser] = args;
 			return {
 				process(doc) {
 					doc.querySelectorAll("picture").forEach(pictureElement => {