move importPrefix into separate file

allow to disable import prefix

Author: sokra

lib/getImportPrefix.js

@@ -0,0 +1,14 @@
+/*
+	MIT License http://www.opensource.org/licenses/mit-license.php
+	Author Tobias Koppers @sokra
+*/
+module.exports = function getImportPrefix(loaderContext, query) {
+	if(query.importLoaders === false)
+		return "";
+	var importLoaders = parseInt(query.importLoaders, 10) || 0;
+	var loadersRequest = loaderContext.loaders.slice(
+		loaderContext.loaderIndex,
+		loaderContext.loaderIndex + 1 + importLoaders
+	).map(function(x) { return x.request; }).join("!");
+	return "-!" + loadersRequest + "!";
+};

lib/loader.js

@@ -5,13 +5,13 @@
 var path = require("path");
 var loaderUtils = require("loader-utils");
 var processCss = require("./processCss");
+var getImportPrefix = require("./getImportPrefix");
 
 
 module.exports = function(content, map) {
 	if(this.cacheable) this.cacheable();
 	var query = loaderUtils.parseQuery(this.query);
 	var root = query.root;
-	var importLoaders = parseInt(query.importLoaders, 10) || 0;
 	var moduleMode = query.module;
 
 	if(typeof map !== "string") {
@@ -30,11 +30,7 @@ module.exports = function(content, map) {
 	var cssAsString = JSON.stringify(result.source);
 
 	// for importing CSS
-	var loadersRequest = this.loaders.slice(
-		this.loaderIndex,
-		this.loaderIndex + 1 + importLoaders
-	).map(function(x) { return x.request; }).join("!");
-	var importUrlPrefix = "-!" + loadersRequest + "!";
+	var importUrlPrefix = getImportPrefix(this, query);
 
 	var alreadyImported = {};
 	var importJs = result.importItems.filter(function(imp) {

lib/localsLoader.js

@@ -4,12 +4,12 @@
 */
 var loaderUtils = require("loader-utils");
 var processCss = require("./processCss");
+var getImportPrefix = require("./getImportPrefix");
 
 
 module.exports = function(content) {
 	if(this.cacheable) this.cacheable();
 	var query = loaderUtils.parseQuery(this.query);
-	var importLoaders = parseInt(query.importLoaders, 10) || 0;
 	var moduleMode = query.module;
 
 	var result = processCss(content, null, {
@@ -20,11 +20,7 @@ module.exports = function(content) {
 	});
 
 	// for importing CSS
-	var loadersRequest = this.loaders.slice(
-		this.loaderIndex,
-		this.loaderIndex + 1 + importLoaders
-	).map(function(x) { return x.request; }).join("!");
-	var importUrlPrefix = "-!" + loadersRequest + "!";
+	var importUrlPrefix = getImportPrefix(this, query);
 
 	function importItemMatcher(item) {
 		var match = result.importItemRegExp.exec(item);