feat: allow user to modify generated webpack config

lib/webpack/client.js

@@ -3,6 +3,7 @@ const webpackNiceLog = require('webpack-nicelog');
 const {StatsWriterPlugin} = require('webpack-stats-plugin');
 const cleanWebpackPlugin = require('clean-webpack-plugin');
 const createBaseConfig = require('./base');
+const {applyChainWebpack} = require('./utils');
 
 module.exports = function createClientConfig(props) {
   const config = createBaseConfig(props);
@@ -21,5 +22,9 @@ module.exports = function createClientConfig(props) {
 
   // show compilation progress bar and build time
   config.plugin('niceLog').use(webpackNiceLog, [{name: 'Client'}]);
+
+  // user extended webpack-chain config
+  applyChainWebpack(props.siteConfig.chainWebpack, config, false);
+
   return config;
 };

lib/webpack/server.js

@@ -2,6 +2,7 @@ const path = require('path');
 const staticSiteGenerator = require('static-site-generator-webpack-plugin');
 const webpackNiceLog = require('webpack-nicelog');
 const createBaseConfig = require('./base');
+const {applyChainWebpack} = require('./utils');
 
 module.exports = function createServerConfig(props) {
   const config = createBaseConfig(props, true);
@@ -32,5 +33,8 @@ module.exports = function createServerConfig(props) {
     .plugin('niceLog')
     .use(webpackNiceLog, [{name: 'Server', color: 'yellow'}]);
 
+  // user extended webpack-chain config
+  applyChainWebpack(props.siteConfig.chainWebpack, config, true);
+
   return config;
 };

lib/webpack/utils.js

@@ -0,0 +1,28 @@
+const merge = require('webpack-merge');
+
+// Modify the generated webpack config with normal webpack config
+function applyConfigureWebpack(userConfig, config, isServer) {
+  if (typeof userConfig === 'object') {
+    return merge(config, userConfig);
+  }
+  if (typeof userConfig === 'function') {
+    const res = userConfig(config, isServer);
+    if (res && typeof res === 'object') {
+      return merge(config, res);
+    }
+  }
+  return config;
+}
+
+// Modify the generated webpack config with webpack-chain API
+function applyChainWebpack(userChainWebpack, config, isServer) {
+  if (userChainWebpack) {
+    userChainWebpack(config, isServer);
+  }
+  
+}
+
+module.exports = {
+  applyConfigureWebpack,
+  applyChainWebpack
+};