make babel optional, tweak peer deps

Author: yyx990803

lib/loader.js

@@ -15,6 +15,13 @@ var styleRewriterPath = normalize.lib('style-rewriter')
 var styleLoaderPath = normalize.dep('vue-style-loader')
 var hotReloadAPIPath = normalize.dep('vue-hot-reload-api')
 
+var hasBabel = true
+try {
+  require('babel-loader')
+} catch (e) {
+  hasBabel = false
+}
+
 var rewriterInjectRE = /\b(css(?:-loader)?(?:\?[^!]+)?)(?:!|$)/
 
 var defaultLang = {
@@ -42,9 +49,11 @@ module.exports = function (content) {
   var defaultLoaders = {
     html: templateCompilerPath + '?id=' + moduleId,
     css: styleLoaderPath + '!css-loader' + (needCssSourceMap ? '?sourceMap' : ''),
-    js: this.options.babel
-      ? 'babel-loader' // respect user options
-      : 'babel-loader?presets[]=es2015&plugins[]=transform-runtime&comments=false'
+    js: hasBabel
+      ? this.options.babel
+        ? 'babel-loader' // respect user options
+        : 'babel-loader?presets[]=es2015&plugins[]=transform-runtime&comments=false'
+      : ''
   }
 
   // check if there are custom loaders specified via

package.json

@@ -40,6 +40,10 @@
     "vue-style-loader": "^1.0.0",
     "vue-template-compiler": "^2.0.0-alpha.2"
   },
+  "peerDependencies": {
+    "css-loader": "^0.23.1",
+    "file-loader": "^0.8.5"
+  },
   "devDependencies": {
     "babel-core": "^6.8.0",
     "babel-loader": "^6.2.4",