feat: allow user to modify generated webpack config

lib/commands/build.js

@@ -6,6 +6,7 @@ const globby = require('globby');
 const load = require('../load');
 const createServerConfig = require('../webpack/server');
 const createClientConfig = require('../webpack/client');
+const {applyConfigureWebpack} = require('../webpack/utils');
 
 function compile(config) {
   return new Promise((resolve, reject) => {
@@ -36,8 +37,15 @@ module.exports = async function build(siteDir, cliOptions = {}) {
 
   const props = await load(siteDir);
 
-  const serverConfig = createServerConfig(props).toConfig();
+  let serverConfig = createServerConfig(props).toConfig();
-  const clientConfig = createClientConfig(props).toConfig();
+  let clientConfig = createClientConfig(props).toConfig();
+
+  // apply user webpack config
+  const {
+    siteConfig: {configureWebpack}
+  } = props;
+  clientConfig = applyConfigureWebpack(configureWebpack, clientConfig, false);
+  serverConfig = applyConfigureWebpack(configureWebpack, serverConfig, true);
 
   // Build the client bundles first.
   // We cannot run them in parallel because the server need to pickup the correct client bundle name

lib/commands/start.js

@@ -13,6 +13,7 @@ const serve = require('webpack-serve');
 const HtmlWebpackPlugin = require('html-webpack-plugin');
 const load = require('../load');
 const createClientConfig = require('../webpack/client');
+const {applyConfigureWebpack} = require('../webpack/utils');
 
 function getHost(reqHost) {
   return reqHost || 'localhost';
@@ -72,6 +73,13 @@ module.exports = async function start(siteDir, cliOptions = {}) {
     }
   ]);
   config = config.toConfig();
+
+  // apply user webpack config
+  const {
+    siteConfig: {configureWebpack}
+  } = props;
+  config = applyConfigureWebpack(configureWebpack, config, false);
+
   const compiler = webpack(config);
 
   // webpack-serve

lib/load/config.js

@@ -21,7 +21,9 @@ module.exports = function loadConfig(siteDir, deleteCache = true) {
   const optionalFields = [
     'customDocsPath',
     'highlight',
-    'markdownPlugins'
+    'markdownPlugins',
+    'configureWebpack',
+    'chainWebpack'
   ];
   const missingFields = requiredFields.filter(field => !config[field]);
   if (missingFields && missingFields.length > 0) {

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
+};

package.json

@@ -81,6 +81,7 @@
     "style-loader": "^0.22.1",
     "webpack": "^4.16.3",
     "webpack-chain": "^4.8.0",
+    "webpack-merge": "^4.1.4",
     "webpack-nicelog": "^2.2.1",
     "webpack-serve": "^2.0.2",
     "webpack-stats-plugin": "^0.2.1"

test/webpack/utils.test.js

@@ -0,0 +1,107 @@
+import {validate} from 'webpack';
+import path from 'path';
+import Config from 'webpack-chain';
+
+import {applyConfigureWebpack, applyChainWebpack} from '@lib/webpack/utils';
+
+describe('extending generated webpack config', () => {
+  test('direct mutation on generated webpack config object', async () => {
+    // fake generated webpack config
+    let config = {
+      output: {
+        path: __dirname,
+        filename: 'bundle.js'
+      }
+    };
+
+    /* eslint-disable */
+    const configureWebpack = (generatedConfig, isServer) => {
+      if (!isServer) {
+        generatedConfig.entry = 'entry.js';
+        generatedConfig.output = {
+          path: path.join(__dirname, 'dist'),
+          filename: 'new.bundle.js'
+        };
+      }
+    };
+    /* eslint-enable */
+
+    config = applyConfigureWebpack(configureWebpack, config, false);
+    expect(config).toEqual({
+      entry: 'entry.js',
+      output: {
+        path: path.join(__dirname, 'dist'),
+        filename: 'new.bundle.js'
+      }
+    });
+    const errors = validate(config);
+
+    console.log(errors);
+    expect(errors.length).toBe(0);
+  });
+
+  test('webpack-merge with user webpack config object', async () => {
+    // fake generated webpack config
+    let config = {
+      output: {
+        path: __dirname,
+        filename: 'bundle.js'
+      }
+    };
+
+    /* eslint-disable */
+    const configureWebpack = {
+      entry: 'entry.js',
+      output: {
+        path: path.join(__dirname, 'dist'),
+        filename: 'new.bundle.js'
+      }
+    };
+    /* eslint-enable */
+
+    config = applyConfigureWebpack(configureWebpack, config, false);
+    expect(config).toEqual({
+      entry: 'entry.js',
+      output: {
+        path: path.join(__dirname, 'dist'),
+        filename: 'new.bundle.js'
+      }
+    });
+    const errors = validate(config);
+    expect(errors.length).toBe(0);
+  });
+
+  test('use webpack-chain API', async () => {
+    // fake generated webpack config in webpack-chain format
+    let config = new Config();
+    config.output.path(__dirname).filename('bundle.js');
+
+    // user chainWebpack
+    /* eslint-disable */
+    const chainWebpack = (oldConfig, isServer) => {
+      if (!isServer) {
+        oldConfig.entry('main').add('./entry.js');
+        oldConfig.output
+          .path(path.join(__dirname, 'dist'))
+          .filename('new.bundle.js');
+      }
+    };
+    /* eslint-enable */
+
+    applyChainWebpack(chainWebpack, config, false);
+
+    // transform to webpack configuration object format
+    config = config.toConfig();
+    expect(config).toEqual({
+      output: {
+        path: path.join(__dirname, 'dist'),
+        filename: 'new.bundle.js'
+      },
+      entry: {
+        main: ['./entry.js']
+      }
+    });
+    const errors = validate(config);
+    expect(errors.length).toBe(0);
+  });
+});

yarn.lock

@@ -6975,6 +6975,12 @@ webpack-log@^1.0.1, webpack-log@^1.1.1, webpack-log@^1.1.2, webpack-log@^1.2.0:
     loglevelnext "^1.0.1"
     uuid "^3.1.0"
 
+webpack-merge@^4.1.4:
+  version "4.1.4"
+  resolved "https://registry.yarnpkg.com/webpack-merge/-/webpack-merge-4.1.4.tgz#0fde38eabf2d5fd85251c24a5a8c48f8a3f4eb7b"
+  dependencies:
+    lodash "^4.17.5"
+
 webpack-nicelog@^2.2.1:
   version "2.2.1"
   resolved "https://registry.yarnpkg.com/webpack-nicelog/-/webpack-nicelog-2.2.1.tgz#e3458003ce0d98966e930657176fb4eb6f536b85"