Enable optional sourcemaps in the Vue template

Author: samtgarson

Diff for: templates/webpack.vue.js

@@ -44,6 +44,7 @@ module.exports = env => {
         production, // --env.production
         report, // --env.report
         hmr, // --env.hmr
+        sourceMap, // --env.sourceMap
     } = env;
 
     const externals = (env.externals || []).map((e) => { // --env.externals
@@ -111,7 +112,7 @@ module.exports = env => {
             "fs": "empty",
             "__dirname": false,
         },
-        devtool: "none",
+        devtool: sourceMap ? "inline-source-map" : "none",
         optimization: {
             splitChunks: {
                 cacheGroups: {