perf: generate source maps only when explicitly set (webpack#478)

Author: evilebottnawi

lib/loader.js

@@ -16,10 +16,16 @@ module.exports = function(content, map) {
 var root = query.root;
 var moduleMode = query.modules || query.module;
 var camelCaseKeys = query.camelCase || query.camelcase;
+var sourceMap = query.sourceMap || false;
 var resolve = createResolver(query.alias);
 
-if(map !== null && typeof map !== "string") {
-map = JSON.stringify(map);
+if(sourceMap) {
+if (map && typeof map !== "string") {
+map = JSON.stringify(map);
+}
+} else {
+// Some loaders (example `"postcss-loader": "1.x.x"`) always generates source map, we should remove it
+map = null;
 }
 
 processCss(content, map, {
@@ -28,7 +34,8 @@ module.exports = function(content, map) {
 to: loaderUtils.getCurrentRequest(this),
 query: query,
 minimize: this.minimize,
-loaderContext: this
+loaderContext: this,
+sourceMap: sourceMap
 }, function(err, result) {
 if(err) return callback(err);
 

lib/processCss.js

@@ -200,12 +200,12 @@ module.exports = function processCss(inputSource, inputMap, options, callback) {
 // we need a prefix to avoid path rewriting of PostCSS
 from: "/css-loader!" + options.from,
 to: options.to,
-map: {
+map: options.sourceMap ? {
 prev: inputMap,
 sourcesContent: true,
 inline: false,
 annotation: false
-}
+} : null
 }).then(function(result) {
 callback(null, {
 source: result.css,

test/sourceMapTest.js

@@ -10,6 +10,24 @@ describe("source maps", function() {
 testWithMap("falsy: undefined map doesn't cause an error", ".class { a: b c d; }", undefined, [
 [1, ".class { a: b c d; }", ""]
 ]);
+ testWithMap("should don't generate sourceMap when `sourceMap: false` and map exist",
+".class { a: b c d; }",
+ {
+ file: 'test.css',
+ mappings: 'AAAA,SAAS,SAAS,EAAE',
+ names: [],
+ sourceRoot: '',
+ sources: [ '/folder/test.css' ],
+ sourcesContent: [ '.class { a: b c d; }' ],
+ version: 3
+ },
+[
+[1, ".class { a: b c d; }", ""]
+],
+{
+ query: "?sourceMap=false"
+}
+);
 testMap("generate sourceMap (1 loader)", ".class { a: b c d; }", undefined, {
 loaders: [{request: "/path/css-loader"}],
 options: { context: "/" },
@@ -95,4 +113,13 @@ describe("source maps", function() {
 version: 3
 }]
 ]);
+testMap("don't generate sourceMap (1 loader)", ".class { a: b c d; }", undefined, {
+loaders: [{request: "/path/css-loader"}],
+options: { context: "/" },
+resource: "/folder/test.css",
+request: "/path/css-loader!/folder/test.css",
+query: "?sourceMap=false"
+}, [
+[1, ".class { a: b c d; }", ""]
+]);
 });