Update the project to Webpack4 (cornerstonejs#248)

* Try to upgrade to Webpack 4. Seems broken

* Switch branch to my Webpack fork for testing

* Updating Webpack: Switch to latest webpack version

* Bump versions of dependencies

* Add uglify plugin, remove dist again

config/webpack/plugins/banner.js

@@ -11,18 +11,18 @@ const getCurrentDate = () => {
   const date = ('0' + today.getDate()).slice(-2);
 
   return `${year}-${month}-${date}`;
-}
+};
 
 const getBanner = () => {
   return `/*! ${pkg.name} - ${pkg.version} - ` +
          `${getCurrentDate()} ` +
          `| (c) 2016 Chris Hafey | https://github.com/cornerstonejs/cornerstone */`
-}
+};
 
 module.exports = () => {
   return new webpack.BannerPlugin({
     banner: getBanner(),
     entryOnly: true,
     raw: true
   });
-}
+};

config/webpack/webpack-base.js

@@ -6,6 +6,7 @@ const outputPath = path.join(rootPath, 'dist');
 const bannerPlugin = require(path.join(__dirname, 'plugins', 'banner.js'));
 
 module.exports = {
+  mode: 'development',
   context: context,
   entry: {
     cornerstone: path.join(context, 'index.js')

config/webpack/webpack-prod.js

@@ -1,15 +1,22 @@
 const webpack = require('webpack');
 const merge = require('./merge');
 const baseConfig = require('./webpack-base');
+const UglifyJSPlugin = require('uglifyjs-webpack-plugin');
+
 const devConfig = {
   output: {
     filename: '[name].min.js'
   },
-  plugins: [
-    new webpack.optimize.UglifyJsPlugin({
-      sourceMap: true
-    })
-  ]
+  mode: "production",
+  optimization: {
+    minimizer: [
+      new UglifyJSPlugin({
+        uglifyOptions: {
+          sourceMap: true
+        }
+      })
+    ]
+  },
 };
 
-module.exports = merge(baseConfig, devConfig);
+module.exports = merge(baseConfig, devConfig);