Optimize build speed (#948)

* Fix incorrect webpack mode argument.

* User terser webpack plugin as build minimizer.

* Use HardSourceWebpackPlugin for webpack caching.

config/webpack.config.js

@@ -2,6 +2,7 @@ const path = require('path');
 const BundleAnalyzerPlugin = require('webpack-bundle-analyzer')
 .BundleAnalyzerPlugin;
 const plugins = require('./webpack.plugins.js');
+const TerserPlugin = require('terser-webpack-plugin');
 
 const commonConfig = ({
     publicPath,
@@ -25,8 +26,7 @@ const commonConfig = ({
         }
     },
     optimization: {
-        minimize: true,
-        concatenateModules: false
+        minimizer: [new TerserPlugin({ sourceMap: true })]
     },
     module: {
         rules: [

config/webpack.plugins.js

@@ -2,9 +2,11 @@ const webpack = require('webpack');
 const LodashWebpackPlugin = require('lodash-webpack-plugin');
 const WriteFileWebpackPlugin = require('write-file-webpack-plugin');
 const { CleanWebpackPlugin } = require('clean-webpack-plugin');
+const HardSourceWebpackPlugin = require('hard-source-webpack-plugin');
 
 const plugins = [
     new CleanWebpackPlugin(),
+    new HardSourceWebpackPlugin(),
     new WriteFileWebpackPlugin(),
     new webpack.SourceMapDevToolPlugin({
         test: /\.js/i,