Fix source map generation.

Author: davidlehn

CHANGELOG.md

@@ -1,5 +1,8 @@
 # jsonld ChangeLog
 
+### Fixed
+- Fix source map generation.
+
 ## 1.2.0 - 2018-12-11
 
 ### Notes

webpack.config.js

@@ -121,13 +121,14 @@ outputs.forEach((info) => {
     devtool: 'cheap-module-source-map',
     plugins: [
       new webpack.optimize.UglifyJsPlugin({
+        //beautify: true,
         compress: {
           warnings: true
         },
         output: {
           comments: false
-        }
-        //beautify: true
+        },
+        sourceMap: true
       })
     ]
   });