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近期在某个高频迭代七年的 Angular 项目升级至 Angular 13 后，其开发模式的构建速度慢、资源占用高，开发体验相当差。在一台仅在开会时偶尔使用的 Macbook air（近期居家办公期间转换为了主要生产力工具） 中启动构建时，它的风扇会呼呼作响，CPU 负荷被打满，而在构建完成后，热更新一次的时间在一分钟以上。【相关教程推荐：《angular教程》】
在经过各种原因分析与排查后，最终在 angular.json 的 schema(./node_modules/@angular/cli/lib/config/schema.json) 中发现了问题，再结合 Angular 12 release 文档定位到了具体原因： Angular 12 一个主要的改动是将 aot、buildOptimizer、optimization 等参数由默认值 false 改为了 true。
A number of browser and server builder options have had their default values changed. The aim of these changes is to reduce the configuration complexity and support the new "production builds by default" initiative.
可以看到 Angular 12 后的默认生产模式，对于跨版本升级来说是比较坑爹的。我们可以从这个提交中了解变动细节：656f8d7
解决办法则是在 development 配置中禁用生产模式相关的配置项。示例：
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"$schema": "./node_modules/@angular/cli/lib/config/schema.json",
"projects": {
"front": {
"architect": {
"build": {
"configurations": {
"development": {
"tsConfig": "./tsconfig.dev.json",
"aot": false,
"buildOptimizer": false,
"optimization": false,
"extractLicenses": false,
"sourceMap": true,
"vendorChunk": true,
"namedChunks": true
}
}
},
}
},
"defaultProject": "front"
}登录后复制需注意 aot 开启与关闭时，在构建结果表现上可能会有一些差异，需视具体问题而分析。
aot 后 pug 编译报错该项目中使用 pug 开发 html 内容。关闭 aot 时构建正常，开启后则会报错。
根据报错内容及位置进行 debugger 调试，可以看到其编译结果为一个 esModule 的对象。这是由于使用了 raw-loader，其编译结果默认为 esModule 模式，禁用 esModule 配置项即可。示例（自定义 webpack 配置可参考下文的 dll 配置相关示例）：
{
test: /\.pug$/,
use: [
{
loader: 'raw-loader',
options: {
esModule: false,
},
},
{
loader: 'pug-html-loader',
options: {
doctype: 'html',
},
},
],
},登录后复制该项目项目构建上有自定义 webpack 配置的需求，使用了 @angular-builders/custom-webpack 库实现，但是没有配置 dll。
Angular 提供了 vendorChunk 参数，开启它会提取在 package.json 中的依赖等公共资源至独立 chunk 中，其可以很好的解决热更新 bundles 过大导致热更新太慢等的问题，但仍然存在较高的内存占用，而且实际的对比测试中，在存在 webpack5 缓存的情况下，其相比 dll 模式的构建编译速度以及热更新速度都稍微慢一些。故对于开发机器性能一般的情况下，给开发模式配置 dll 是会带来一定的收益的。
首先需要配置自定义 webpack 配置的构建支持。执行如下命令添加依赖：
npm i -D @angular-builders/custom-webpack
登录后复制修改 angluar.json 配置。内容格式参考：
{
"$schema": "./node_modules/@angular/cli/lib/config/schema.json",
"cli": {
"analytics": false,
"cache": {
"path": "node_modules/.cache/ng"
}
},
"version": 1,
"newProjectRoot": "projects",
"projects": {
"front": {
"root": "",
"sourceRoot": "src",
"projectType": "application",
"prefix": "app",
"schematics": {
"@schematics/angular:component": {
"style": "less"
}
},
"architect": {
"build": {
"builder": "@angular-builders/custom-webpack:browser",
"options": {
"customWebpackConfig": {
"path": "./webpack.config.js"
},
"indexTransform": "scripts/index-html-transform.js",
"outputHashing": "media",
"deleteOutputPath": true,
"watch": true,
"sourceMap": false,
"outputPath": "dist/dev",
"index": "src/index.html",
"main": "src/app-main.ts",
"polyfills": "src/polyfills.ts",
"tsConfig": "./tsconfig.app.json",
"baseHref": "./",
"assets": [
"src/assets/",
{
"glob": "**/*",
"input": "./node_modules/@ant-design/icons-angular/src/inline-svg/",
"output": "/assets/"
}
],
"styles": [
"node_modules/angular-tree-component/dist/angular-tree-component.css",
"src/css/index.less"
],
"scripts": []
},
"configurations": {
"development": {
"tsConfig": "./tsconfig.dev.json",
"buildOptimizer": false,
"optimization": false,
"aot": false,
"extractLicenses": false,
"sourceMap": true,
"vendorChunk": true,
"namedChunks": true,
"scripts": [
{
"inject": true,
"input": "./dist/dll/dll.js",
"bundleName": "dll_library"
}
]
},
"production": {
"outputPath": "dist/prod",
"baseHref": "./",
"watch": false,
"fileReplacements": [
{
"replace": "src/environments/environment.ts",
"with": "src/environments/environment.prod.ts"
}
],
"optimization": {
"scripts": true,
"styles": {
"minify": true,
"inlineCritical": false
},
"fonts": true
},
"outputHashing": "all",
"sourceMap": false,
"namedChunks": false,
"aot": true,
"extractLicenses": false,
"vendorChunk": false,
"buildOptimizer": true
}
},
"defaultConfiguration": "production"
},
"serve": {
"builder": "@angular-builders/custom-webpack:dev-server",
"options": {
"browserTarget": "front:build",
"liveReload": false,
"open": false,
"host": "0.0.0.0",
"port": 3002,
"servePath": "/",
"publicHost": "localhost.gf.com.cn",
"proxyConfig": "config/ngcli-proxy-config.js",
"disableHostCheck": true
},
"configurations": {
"production": {
"browserTarget": "front:build:production"
},
"development": {
"browserTarget": "front:build:development"
}
},
"defaultConfiguration": "development"
},
"test": {
"builder": "@angular-builders/custom-webpack:karma",
"options": {
"customWebpackConfig": {
"path": "./webpack.test.config.js"
},
"indexTransform": "scripts/index-html-transform.js",
"main": "src/ngtest.ts",
"polyfills": "src/polyfills.ts",
"tsConfig": "./tsconfig.spec.json",
"karmaConfig": "./karma.conf.js",
"assets": [
"src/assets/",
{
"glob": "**/*",
"input": "./node_modules/@ant-design/icons-angular/src/inline-svg/",
"output": "/assets/"
}
],
"styles": [
"node_modules/angular-tree-component/dist/angular-tree-component.css",
"src/css/index.less"
],
"scripts": []
}
}
}
}
},
"defaultProject": "front",
"schematics": {
"@schematics/angular:module": {
"routing": true,
"spec": false
},
"@schematics/angular:component": {
"flat": false,
"inlineStyle": true,
"inlineTemplate": false
}
}
}登录后复制该示例中涉及多处自定义配置内容，主要需注意 webpack 相关的部分， 其他内容可视自身项目具体情况对比参考。一些细节也可参考以前的这篇文章中的实践介绍：lzw.me/a/update-to…
新建 webpack.config.js 文件。内容参考：
const { existsSync } = require('node:fs');
const { resolve } = require('node:path');
const webpack = require('webpack');
// require('events').EventEmitter.defaultMaxListeners = 0;
/**
* @param {import('webpack').Configuration} config
* @param {import('@angular-builders/custom-webpack').CustomWebpackBrowserSchema} options
* @param {import('@angular-builders/custom-webpack').TargetOptions} targetOptions
*/
module.exports = (config, options, targetOptions) => {
if (!config.devServer) config.devServer = {};
config.plugins.push(
new webpack.DefinePlugin({ LZWME_DEV: config.mode === 'development' }),
);
const dllDir = resolve(__dirname, './dist/dll');
if (
existsSync(dllDir) &&
config.mode === 'development' &&
options.scripts?.some((d) => d.bundleName === 'dll_library')
) {
console.log('use dll:', dllDir);
config.plugins.unshift(
new webpack.DllReferencePlugin({
manifest: require(resolve(dllDir, 'dll-manifest.json')),
context: __dirname,
})
);
}
config.module.rules = config.module.rules.filter((d) => {
if (d.test instanceof RegExp) {
// 使用 less，移除 sass/stylus loader
return !(d.test.test('x.sass') || d.test.test('x.scss') || d.test.test('x.styl'));
}
return true;
});
config.module.rules.unshift(
{
test: /\.pug$/,
use: [
{
loader: 'raw-loader',
options: {
esModule: false,
},
},
{
loader: 'pug-html-loader',
options: {
doctype: 'html',
},
},
],
},
{
test: /\.html$/,
loader: 'raw-loader',
exclude: [helpers.root('src/index.html')],
},
{
test: /\.svg$/,
loader: 'raw-loader',
},
{
test: /\.(t|les)s/,
loader: require.resolve('@lzwme/strip-loader'),
exclude: /node_modules/,
options: {
disabled: config.mode !== 'production',
},
}
);
// AngularWebpackPlugin，用于自定义 index.html 处理插件
const awPlugin = config.plugins.find((p) => p.options?.hasOwnProperty('directTemplateLoading'));
if (awPlugin) awPlugin.pluginOptions.directTemplateLoading = false;
// 兼容上古遗传逻辑，禁用部分插件
config.plugins = config.plugins.filter((plugin) => {
const pluginName = plugin.constructor.name;
if (/CircularDependency|CommonJsUsageWarnPlugin/.test(pluginName)) {
console.log('[webpack][plugin] disabled: ', pluginName);
return false;
}
return true;
});
// console.log('[webpack][config]', config.mode, config, options, targetOptions);
return config;
};登录后复制新建 webpack.dll.mjs 文件，用于 dll 构建。内容示例：
import { join } from 'node:path';
import webpack from 'webpack';
const rootDir = process.cwd();
const isDev = process.argv.slice(2).includes('--dev') || process.env.NODE_ENV === 'development';
/** @type {import('webpack').Configuration} */
const config = {
context: rootDir,
mode: isDev ? 'development' : 'production',
entry: {
dll: [
'@angular/common',
'@angular/core',
'@angular/forms',
'@angular/platform-browser',
'@angular/platform-browser-dynamic',
'@angular/router',
'@lzwme/asmd-calc',
// more...
],
},
output: {
path: join(rootDir, 'dist/dll'),
filename: 'dll.js',
library: '[name]_library',
},
plugins: [
new webpack.DllPlugin({
path: join(rootDir, 'dist/dll/[name]-manifest.json'),
name: '[name]_library',
}),
new webpack.IgnorePlugin({
resourceRegExp: /^\.\/locale$/,
contextRegExp: /moment$/,
}),
],
cache: { type: 'filesystem' },
};
webpack(config).run((err, result) => {
console.log(err ? `Failed!` : `Success!`, err || `${result.endTime - result.startTime}ms`);
});登录后复制在 angular.json 中添加 dll.js 文件的注入配置，可参考前文示例中 development.scripts 中的配置内容格式。
在 package.json 中增加启动脚本配置。示例：
{
"scripts": {
"ng:serve": "node --max_old_space_size=8192 node_modules/@angular/cli/bin/ng serve",
"dll": "node config/webpack.dll.mjs",
"dev": "npm run dll -- --dev && npm run ng:serve -- -c development",
}
}登录后复制最后，可执行 npm run dev 测试效果是否符合预期。
angular-cli 在升级至 webpack 5 以后，基于 webpack 5 的缓存能力做了许多编译优化，一般情况下开发模式二次构建速度相比之前会有大幅的提升。但是相比 snowpack 和 vite 一类的 esm no bundles 方案仍有较大的差距。其从 Angular 13 开始已经在尝试引入 esbuild，但由于其高度定制化的构建逻辑适配等问题，对一些配置参数的兼容支持相对较为复杂。在 Angular 15 中已经可以进行生产级配置尝试了，有兴趣也可作升级配置与尝试。
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