tweak style codegen for server-side rendering

Author: yyx990803

lib/loader.js

@@ -47,15 +47,21 @@ module.exports = function (content) {
   var moduleId = 'data-v-' + genId(filePath)
   var styleRewriter = styleRewriterPath + '?id=' + moduleId
 
-  var needCssSourceMap =
-    !isProduction &&
-    this.sourceMap &&
-    options.cssSourceMap !== false
+  var cssLoaderOptions = ''
+  if (!isProduction && this.sourceMap && options.cssSourceMap !== false) {
+    cssLoaderOptions += '?sourceMap'
+  }
+  if (isProduction) {
+    cssLoaderOptions += (cssLoaderOptions ? '&' : '?') + 'minimize'
+  }
+
+  var bubleOptions = hasBuble && options.buble
+    ? '?' + JSON.stringify(options.buble)
+    : ''
 
-  var bubleOptions = hasBuble && options.buble ? '?' + JSON.stringify(options.buble) : ''
   var defaultLoaders = {
     html: templateCompilerPath + '?id=' + moduleId,
-    css: (isServer ? '' : styleLoaderPath + '!') + 'css-loader' + (needCssSourceMap ? '?sourceMap' : ''),
+    css: styleLoaderPath + '!' + 'css-loader' + cssLoaderOptions,
     js: hasBuble ? ('buble-loader' + bubleOptions) : hasBabel ? 'babel-loader' : ''
   }
 
@@ -205,14 +211,12 @@ module.exports = function (content) {
     output += '\n/* styles */\n'
     var hasModules = false
     parts.styles.forEach(function (style, i) {
-      var moduleName = (style.module === true) ? '$style' : style.module
-
       // require style
-      if (isServer && !moduleName) return
       var requireString = style.src
         ? getRequireForImport('styles', style, style.scoped)
         : getRequire('styles', style, i, style.scoped)
 
+      var moduleName = (style.module === true) ? '$style' : style.module
       // setCssModule
       if (moduleName) {
         if (!hasModules) {
@@ -225,10 +229,10 @@ module.exports = function (content) {
         } else {
           cssModules[moduleName] = true
 
-          // `style-loader` exposes the name-to-hash map directly
+          // `(vue-)style-loader` exposes the name-to-hash map directly
           // `css-loader` exposes it in `.locals`
-          // We drop `style-loader` in SSR, and add `.locals` here.
-          if (isServer) {
+          // add `.locals` if the user configured to not use style-loader.
+          if (requireString.indexOf('style-loader') < 0) {
             requireString += '.locals'
           }