properly support sourcemaps in style-rewriter

Author: yyx990803

lib/style-rewriter.js

@@ -30,18 +30,21 @@ var addId = postcss.plugin('add-id', function () {
   }
 })
 
-module.exports = function (css) {
+module.exports = function (css, map) {
   this.cacheable()
   var cb = this.async()
 
   var query = loaderUtils.parseQuery(this.query)
   var options = this.options.vue || {}
   var autoprefixOptions = options.autoprefixer
+  var plugins = []
 
-  var processors = []
+  // scoped css
   if (query.scoped) {
-    processors.push(addId)
+    plugins.push(addId)
   }
+
+  // autoprefixer
   if (autoprefixOptions !== false) {
     autoprefixOptions = assign(
       {},
@@ -50,14 +53,29 @@ module.exports = function (css) {
       autoprefixOptions
     )
     var autoprefixer = require('autoprefixer')(autoprefixOptions)
-    processors.push(autoprefixer)
+    plugins.push(autoprefixer)
+  }
+
+  // postcss options, for source maps
+  var file = loaderUtils.getRemainingRequest(this)
+  var opts
+  opts = {
+    from: file,
+    to: file,
+    map: {
+      inline: false,
+      annotation: false
+    }
+  }
+  if (map) {
+    opts.map.prev = map
   }
 
   currentId = '_v-' + hash(this.resourcePath)
-  postcss(processors)
-    .process(css)
+  postcss(plugins)
+    .process(css, opts)
     .then(function (result) {
-      cb(null, result)
+      cb(null, result.css, result.map)
     })
     .catch(function (e) {
       console.log(e)