Update uglify plugin to support es6

packages/0x.js/package.json

@@ -17,7 +17,7 @@
     "scripts": {
         "watch_without_deps": "tsc -w",
         "build": "yarn build:all",
-        "build:all": "run-p build:umd:prod build:commonjs; exit 0;",
+        "build:all": "run-p build:umd:prod build:commonjs",
         "lint": "tslint --project . --exclude **/src/generated_contract_wrappers/**/*",
         "test:circleci": "run-s test:coverage",
         "test": "yarn run_mocha",
@@ -70,6 +70,7 @@
         "tslint": "5.11.0",
         "typedoc": "0.12.0",
         "typescript": "3.0.1",
+        "uglifyjs-webpack-plugin": "^1.3.0",
         "webpack": "^3.1.0"
     },
     "dependencies": {

packages/0x.js/webpack.config.js

@@ -3,6 +3,7 @@
  */
 const _ = require('lodash');
 const webpack = require('webpack');
+const UglifyJsPlugin = require('uglifyjs-webpack-plugin');
 const path = require('path');
 const production = process.env.NODE_ENV === 'production';
 
@@ -27,10 +28,16 @@ module.exports = {
     },
     devtool: 'source-map',
     plugins: [
-        new webpack.optimize.UglifyJsPlugin({
-            minimize: true,
+        // TODO: Revert to webpack bundled version with webpack v4.
+        // The v3 series bundled version does not support ES6 and
+        // fails to build.
+        new UglifyJsPlugin({
             sourceMap: true,
-            include: /\.min\.js$/,
+            uglifyOptions: {
+                mangle: {
+                    reserved: ['BigNumber'],
+                },
+            },
         }),
     ],
     module: {