Move to webpack 4

This has uglification built in.

Closes #42

package.json

@@ -16,27 +16,28 @@
     "babel-plugin-transform-react-jsx": "^6.24.1",
     "babel-preset-env": "^1.5.2",
     "chrome-remote-interface": "^0.25.5",
-    "compression-webpack-plugin": "~1.0.0",
-    "copy-webpack-plugin": "~3.0.1",
+    "compression-webpack-plugin": "^1.1.11",
+    "copy-webpack-plugin": "^4.5.2",
     "css-loader": "^0.28.11",
     "eslint": "^5.4.0",
     "eslint-config-standard": "^11.0.0",
     "eslint-config-standard-react": "^6.0.0",
-    "eslint-loader": "~1.6.1",
+    "eslint-loader": "^2.1.0",
     "eslint-plugin-flowtype": "^2.50.0",
     "eslint-plugin-import": "^2.14.0",
     "eslint-plugin-node": "^7.0.1",
     "eslint-plugin-promise": "^4.0.0",
     "eslint-plugin-react": "^6.9.0",
     "eslint-plugin-standard": "^3.1.0",
-    "extract-text-webpack-plugin": "^2.1.0",
+    "extract-text-webpack-plugin": "^4.0.0-beta.0",
     "htmlparser": "^1.7.7",
     "jed": "^1.1.1",
     "po2json": "^0.4.5",
     "sass-loader": "^7.0.3",
     "sizzle": "^2.3.3",
     "stdio": "^0.2.7",
-    "webpack": "^2.6.1"
+    "webpack": "^4.17.1",
+    "webpack-cli": "^3.1.0"
   },
   "dependencies": {
     "node-sass": "^4.9.0",

webpack.config.js

@@ -78,24 +78,12 @@ info.files.forEach(function(value) {
 info.files = files;
 
 var plugins = [
-    new webpack.DefinePlugin({
-        'process.env': {
-            'NODE_ENV': JSON.stringify(production ? 'production' : 'development')
-        }
-    }),
     new copy(info.files),
     new extract("[name].css")
 ];
 
 /* Only minimize when in production mode */
 if (production) {
-    plugins.unshift(new webpack.optimize.UglifyJsPlugin({
-        beautify: true,
-        compress: {
-            warnings: false
-        },
-    }));
-
     /* Rename output files when minimizing */
     output.filename = "[name].min.js";
 
@@ -108,6 +96,7 @@ if (production) {
 }
 
 module.exports = {
+    mode: production ? 'production' : 'development',
     entry: info.entries,
     externals: externals,
     output: output,