don't take into account srcset URLs when identifying duplicate images

lib/single-file/single-file-core.js

@@ -258,16 +258,26 @@ this.SingleFileCore = this.SingleFileCore || (() => {
 	class BatchRequest {
 		constructor() {
 			this.requests = new Map();
+			this.duplicates = new Map();
 		}
 
-		async addURL(resourceURL, asDataURI = true) {
+		async addURL(resourceURL, asDataURI, groupDuplicates) {
 			return new Promise((resolve, reject) => {
 				const requestKey = JSON.stringify([resourceURL, asDataURI]);
-				const resourceRequests = this.requests.get(requestKey);
-				if (resourceRequests) {
-					resourceRequests.push({ resolve, reject });
-				} else {
-					this.requests.set(requestKey, [{ resolve, reject }]);
+				let resourceRequests = this.requests.get(requestKey);
+				if (!resourceRequests) {
+					resourceRequests = [];
+					this.requests.set(requestKey, resourceRequests);
+				}
+				const callbacks = { resolve, reject };
+				resourceRequests.push(callbacks);
+				if (groupDuplicates) {
+					let duplicateRequests = this.duplicates.get(requestKey);
+					if (!duplicateRequests) {
+						duplicateRequests = [];
+						this.duplicates.set(requestKey, duplicateRequests);
+					}
+					duplicateRequests.push(callbacks);
 				}
 			});
 		}
@@ -286,7 +296,11 @@ this.SingleFileCore = this.SingleFileCore || (() => {
 					const content = await DocUtil.getContent(resourceURL, { asDataURI, maxResourceSize: options.maxResourceSize, maxResourceSizeEnabled: options.maxResourceSizeEnabled });
 					indexResource = indexResource + 1;
 					onloadListener({ index: indexResource, url: resourceURL });
-					resourceRequests.forEach(resourceRequest => resourceRequest.resolve({ content: content.data, indexResource, duplicate: Boolean(resourceRequests.length > 1) }));
+					resourceRequests.forEach(callbacks => {
+						const duplicateCallbacks = this.duplicates.get(requestKey);
+						const duplicate = duplicateCallbacks && duplicateCallbacks.length > 1 && duplicateCallbacks.includes(callbacks);
+						callbacks.resolve({ content: content.data, indexResource, duplicate });
+					});
 				} catch (error) {
 					indexResource = indexResource + 1;
 					onloadListener({ index: indexResource, url: resourceURL });
@@ -1272,7 +1286,7 @@ this.SingleFileCore = this.SingleFileCore || (() => {
 							const resourceURL = Util.normalizeURL(originalResourceURL);
 							if (!Util.testIgnoredPath(resourceURL)) {
 								if (Util.testValidURL(resourceURL, baseURI, options.url)) {
-									let { content } = await batchRequest.addURL(resourceURL);
+									let { content } = await batchRequest.addURL(resourceURL, true);
 									let validResource = content == EMPTY_DATA_URI || content.startsWith(PREFIX_DATA_URI_VND) || content.startsWith(PREFIX_DATA_URI_IMAGE_SVG);
 									if (!validResource) {
 										validResource = await DocUtil.validFont(urlFunction);
@@ -1302,7 +1316,7 @@ this.SingleFileCore = this.SingleFileCore || (() => {
 						const resourceURL = Util.normalizeURL(originalResourceURL);
 						if (!Util.testIgnoredPath(resourceURL)) {
 							if (Util.testValidURL(resourceURL, baseURI, options.url)) {
-								let { content, indexResource, duplicate } = await batchRequest.addURL(resourceURL);
+								let { content, indexResource, duplicate } = await batchRequest.addURL(resourceURL, true, true);
 								if (duplicate && options.groupDuplicateImages) {
 									const tokens = [];
 									findURLToken(originalResourceURL, declaration.value.children, (token, parent) => {
@@ -1345,7 +1359,7 @@ this.SingleFileCore = this.SingleFileCore || (() => {
 							// ignored
 						}
 						if (Util.testValidURL(resourceURL, baseURI, options.url)) {
-							const { content, indexResource, duplicate } = await batchRequest.addURL(resourceURL);
+							const { content, indexResource, duplicate } = await batchRequest.addURL(resourceURL, true, resourceElement.tagName == "IMG" && attributeName == "src");
 							if (removeElementIfMissing && content == EMPTY_DATA_URI) {
 								resourceElement.remove();
 							} else {
@@ -1384,7 +1398,7 @@ this.SingleFileCore = this.SingleFileCore || (() => {
 					}
 					if (Util.testValidURL(resourceURL, baseURI, options.url)) {
 						try {
-							const { content } = await batchRequest.addURL(resourceURL, false);
+							const { content } = await batchRequest.addURL(resourceURL);
 							const DOMParser = DocUtil.getParser();
 							if (DOMParser) {
 								const svgDoc = new DOMParser().parseFromString(content, "image/svg+xml");
@@ -1424,7 +1438,7 @@ this.SingleFileCore = this.SingleFileCore || (() => {
 								// ignored
 							}
 							if (Util.testValidURL(resourceURL, baseURI, options.url)) {
-								const { content } = await batchRequest.addURL(resourceURL);
+								const { content } = await batchRequest.addURL(resourceURL, true);
 								if (!content.startsWith(prefixDataURI) && !content.startsWith(PREFIX_DATA_URI_NO_MIMETYPE) && !content.match(PREFIX_DATA_URI_OCTET_STREAM) && !content.match(PREFIX_DATA_URI_NULL_STREAM)) {
 									resourceElement.setAttribute(attributeName, EMPTY_IMAGE);
 								}