document and test chunk merging

README.md

@@ -522,6 +522,16 @@ You can also save this options object in a JSON file and use it with the shell c
  // normal loaders. This cannot be overridden in the require call.
  // You must pass a string instead of a RegExp if you use workers
 
+ maxChunks: 5, // (experimental)
+ // default: undefined
+ // limit the maximum number of chunks.
+ // chunks are merged until the required number is reached
+
+ mergeSizeRatio: 2, // (experimental)
+ // default: 0.2
+ // when choosing the merged chunks the maximum of this formular is searched:
+ // sizeSaveByChunkMerging - mergedChunkSize * mergeSizeRatio
+
  workers: true,
  // default: false
  // options: true, false, number > 0, object of type webpack/lib/Workers

lib/buildDeps.js

@@ -78,7 +78,7 @@ module.exports = function buildDeps(context, mainModule, options, callback) {
 
 		if(options.maxChunks) {
 			while(depTree.chunkCount > options.maxChunks) {
-				if(!removeOneChunk(depTree, true))
+				if(!removeOneChunk(depTree, options, true))
 					break;
 			}
 		}
@@ -747,7 +747,7 @@ function moduleSize(depTree, moduleId) {
 	return depTree.modulesById[moduleId].source && depTree.modulesById[moduleId].source.length || 0;
 }
 
-function removeOneChunk(depTree, force) {
+function removeOneChunk(depTree, options, force) {
 	var chunks = [];
 	for(var chunkId in depTree.chunks) {
 		var chunk = depTree.chunks[chunkId];
@@ -775,7 +775,7 @@ function removeOneChunk(depTree, force) {
 						sizeMerged += size + 10;
 				}
 			}
-			var value = sizeSum * 2 - sizeMerged;
+			var value = sizeSum - sizeMerged * (options.mergeSizeRatio === undefined ? 1.2 : options.mergeSizeRatio + 1);
 			if(best == null || best[0] < value)
 				best = [value, chunkA.id, chunkB.id];
 		});

test/browsertest/libary2config.js

@@ -10,5 +10,6 @@ module.exports = {
 				}
 			]
 		}
-	}
+	},
+	maxChunks: 2
 }

test/browsertest/node_modules/libary2/lib/main.js

@@ -9,6 +9,10 @@ require.ensure("./extra", function(require) {
 		asnycOk2 = true;
 		window.test(require("./extra") === "Lib2 extra2 with post loader", "Lib2 extra loaded");
 		window.test(sameTick, "Lib2 Should be in the same tick, as it is a empty chunk");
+		require.ensure(["./test.js"], function(require) {
+			window.test(require("./test.js") === "test module", "Lib2 recursive require.ensure");
+			window.test(sameTick, "Lib2 Should be in the same tick, as it should be merged into one chunk");
+		});
 	});
 	sameTick = false;
 });

test/browsertest/node_modules/libary2/lib/test.js

@@ -0,0 +1 @@
+module.exports = "test module";