refractor filename modify logic

README.md

@@ -68,7 +68,7 @@ new ExtractTextPlugin(options: filename | object)
 |Name|Type|Description|
 |:--:|:--:|:----------|
 |**`id`**|`{String}`|Unique ident for this plugin instance. (For advanced usage only, by default automatically generated)|
-|**`filename`**|`{String}`|Name of the result file. May contain `[name]`, `[id]` and `[contenthash]`|
+|**`filename`**|`{String|Object}`|Name of the result file. May contain `[name]`, `[id]` and `[contenthash]`|
 |**`allChunks`**|`{Boolean}`|Extract from all additional chunks too (by default it extracts only from the initial chunk(s))|
 |**`disable`**|`{Boolean}`|Disables the plugin|
 |**`ignoreOrder`**|`{Boolean}`|Disables order check (useful for CSS Modules!), `false` by default|
@@ -155,6 +155,29 @@ module.exports = {
 }
 ```
 
+### Modify filename
+
+`filename` paramter could be `Object`. It accepts `format` and `modify` callback as attributes.
+In the following config, before `modify` callback is called, the css path would be `css/js/a.css`.
+After `modify` callback, it is transformed to `css/a.css`.
+
+```js
+entry: {
+  'js/a': "./a"
+},
+plugins: [
+  new ExtractTextPlugin({
+    filename:  {
+      format: 'css/[name].css',
+      modify: (filename) => {
+        return filename.replace('css/js', 'css');
+      }
+    },
+    allChunks: true
+  })
+]
+```
+
 <h2 align="center">Maintainer</h2>
 
 <table>

index.js

@@ -152,6 +152,18 @@ function isString(a) {
 	return typeof a === "string";
 }
 
+function isObject(a) {
+	return isType('Object', a);
+}
+
+function isFunction(a) {
+	return isType('Function', a);
+}
+
+function isType(type, obj) {
+	return Object.prototype.toString.call(obj) === '[object ' + type + ']';
+}
+
 ExtractTextPlugin.loader = function(options) {
 	return { loader: require.resolve("./loader"), options: options };
 };
@@ -317,11 +329,23 @@ ExtractTextPlugin.prototype.apply = function(compiler) {
 					});
 					var chunk = extractedChunk.originalChunk;
 					var source = this.renderExtractedChunk(extractedChunk);
-					var file = compilation.getPath(filename, {
+
+					var format = filename;
+
+					if (isObject(filename)) {
+						format = filename.format;
+					}
+
+					var file = compilation.getPath(format, {
 						chunk: chunk
 					}).replace(/\[(?:(\w+):)?contenthash(?::([a-z]+\d*))?(?::(\d+))?\]/ig, function() {
 						return loaderUtils.getHashDigest(source.source(), arguments[1], arguments[2], parseInt(arguments[3], 10));
 					});
+
+					if (isFunction(filename.modify)) {
+						file = filename.modify(file);
+					}
+
 					compilation.assets[file] = source;
 					chunk.files.push(file);
 				}

schema/plugin-schema.json

@@ -21,7 +21,10 @@
     },
     "filename": {
       "description": "The filename and path that ExtractTextPlugin will extract to",
-      "type": "string"
+      "modes": {
+        "type": "string",
+        "type": "object"
+      }
     },
     "ignoreOrder": {
       "description": "Ignore dependency order (useful for CSS Modules)",

test/cases/multiple-entries-filename/a.js

@@ -0,0 +1,4 @@
+require.ensure([], function() {
+	require("./a.txt");
+	require("./b.txt");
+});

test/cases/multiple-entries-filename/a.txt

@@ -0,0 +1 @@
+a

test/cases/multiple-entries-filename/b.js

@@ -0,0 +1,4 @@
+require.ensure([], function() {
+	require("./a.txt");
+	require("./c.txt");
+});

test/cases/multiple-entries-filename/b.txt

@@ -0,0 +1 @@
+b

test/cases/multiple-entries-filename/c.txt

@@ -0,0 +1 @@
+c

test/cases/multiple-entries-filename/expected/txt/a.txt

@@ -0,0 +1,2 @@
+a
+b

test/cases/multiple-entries-filename/expected/txt/b.txt

@@ -0,0 +1,2 @@
+a
+c

test/cases/multiple-entries-filename/webpack.config.js

@@ -0,0 +1,18 @@
+var ExtractTextPlugin = require("../../../");
+module.exports = {
+	entry: {
+		'js/a': "./a",
+		'js/b': "./b"
+	},
+	plugins: [
+		new ExtractTextPlugin({
+			filename:  {
+				format: 'txt/[name].txt',
+				modify: (filename) => {
+					return filename.replace('txt/js', 'txt');
+				}
+			},
+			allChunks: true
+		})
+	]
+};