Split the map among the chunks

lib/Chunk.js

@@ -607,10 +607,10 @@ class Chunk {
 		return result;
 	}
 
-	getChildIdsByOrdersMap(includeImmediateChildren) {
+	getChildIdsByOrdersMap() {
 		const chunkMaps = Object.create(null);
 
-		function addChunkChildrenToMap(chunk) {
+		for (const chunk of this.getAllAsyncChunks()) {
 			const data = chunk.getChildIdsByOrders();
 			for (const key of Object.keys(data)) {
 				let chunkMap = chunkMaps[key];
@@ -620,15 +620,6 @@ class Chunk {
 				chunkMap[chunk.id] = data[key];
 			}
 		}
-
-		for (const chunk of this.getAllAsyncChunks()) {
-			addChunkChildrenToMap(chunk);
-		}
-
-		if (includeImmediateChildren) {
-			addChunkChildrenToMap(this);
-		}
-
 		return chunkMaps;
 	}
 

lib/web/JsonpChunkTemplatePlugin.js

@@ -31,6 +31,16 @@ class JsonpChunkTemplatePlugin {
 				);
 				if (entries.length > 0) {
 					source.add(`,${JSON.stringify(entries)}`);
+				} else {
+					source.add(`,null`);
+				}
+				if (
+					chunk.getChildIdsByOrders().prefetch &&
+					chunk.getChildIdsByOrders().prefetch.length
+				) {
+					source.add(
+						`,${JSON.stringify(chunk.getChildIdsByOrders().prefetch)}`
+					);
 				}
 				source.add("])");
 				return source;

lib/web/JsonpMainTemplatePlugin.js

@@ -330,7 +330,6 @@ class JsonpMainTemplatePlugin {
 			(source, chunk, hash) => {
 				if (needChunkLoadingCode(chunk)) {
 					const withDefer = needEntryDeferringCode(chunk);
-					const chunkMap = chunk.getChildIdsByOrdersMap(true).prefetch;
 					return Template.asString([
 						source,
 						"",
@@ -340,6 +339,7 @@ class JsonpMainTemplatePlugin {
 							"var chunkIds = data[0];",
 							"var moreModules = data[1];",
 							withDefer ? "var executeModules = data[2];" : "",
+							"var prefetchChunks = data[3] || []",
 							'// add "moreModules" to the modules object,',
 							'// then flag all "chunkIds" as loaded and fire callback',
 							"var moduleId, chunkId, i = 0, resolves = [];",
@@ -382,31 +382,18 @@ class JsonpMainTemplatePlugin {
 								: "",
 							"",
 							"// chunk prefetching for javascript",
-							"",
-							`var chunkPrefetchMap = ${JSON.stringify(chunkMap, null, "\t")}`,
-							"",
-							"for(let j = 0;j < chunkIds.length; j++) {",
+							"var head = document.getElementsByTagName('head')[0];",
+							"prefetchChunks.forEach(function(chunkId) {",
 							Template.indent([
-								"chunkId = chunkIds[j];",
-								"var chunkPrefetchData = chunkPrefetchMap[chunkId];",
-								"if(chunkPrefetchData) {",
+								"if(installedChunks[chunkId] === undefined) {",
 								Template.indent([
-									"var head = document.getElementsByTagName('head')[0];",
-									"chunkPrefetchData.forEach(function(chunkId) {",
-									Template.indent([
-										"if(installedChunks[chunkId] === undefined) {",
-										Template.indent([
-											"installedChunks[chunkId] = null;",
-											mainTemplate.hooks.linkPrefetch.call("", chunk, hash),
-											"head.appendChild(link);"
-										]),
-										"}"
-									]),
-									"});"
+									"installedChunks[chunkId] = null;",
+									mainTemplate.hooks.linkPrefetch.call("", chunk, hash),
+									"head.appendChild(link);"
 								]),
 								"}"
 							]),
-							"}"
+							"});"
 						]),
 						"};",
 						withDefer
@@ -474,7 +461,11 @@ class JsonpMainTemplatePlugin {
 				if (needChunkLoadingCode(chunk)) {
 					return Template.asString([
 						source,
-						`webpackJsonpCallback([${JSON.stringify(chunk.ids)}, {}])`
+						`webpackJsonpCallback([${JSON.stringify(
+							chunk.ids
+						)}, {}, null, ${JSON.stringify(
+							chunk.getChildIdsByOrders().prefetch
+						)}])`
 					]);
 				}
 				return source;