Allow vue-loader to user PostCSS options as object and custom syntax (#240)

* Allow vue-loader to user PostCSS options as object and custom syntax like SugarSS

* Fix error reported by eslint

* Better testing of available options to avoid complain about undefined properties

* Allow postcss to use a PostCSS options object

* Fix error option is undefined

Author: esiao

lib/style-rewriter.js

@@ -40,6 +40,8 @@ module.exports = function (css, map) {
   var plugins = options.postcss
   if (typeof plugins === 'function') {
     plugins = plugins.call(this, this)
+  } else if (typeof options.postcss === 'object' && options.postcss.plugins) {
+    plugins = options.postcss.plugins
   }
   plugins = plugins ? plugins.slice() : [] // make sure to copy it
 
@@ -72,7 +74,8 @@ module.exports = function (css, map) {
     this.sourceMap &&
     !this.minimize &&
     options.cssSourceMap !== false &&
-    process.env.NODE_ENV !== 'production'
+    process.env.NODE_ENV !== 'production' &&
+    !options.postcss.options.map
   ) {
     opts.map = {
       inline: false,
@@ -81,6 +84,15 @@ module.exports = function (css, map) {
     }
   }
 
+  // postcss options from configuration
+  if (options.postcss && options.postcss.options) {
+    for (var option in options.postcss.options) {
+      if (!opts.hasOwnProperty(option)) {
+        opts[option] = options.postcss.options[option]
+      }
+    }
+  }
+
   postcss(plugins)
     .process(css, opts)
     .then(function (result) {