Detailed explanation of Angular CLI construction and Serve usage

This time I will bring you a detailed explanation of Angular CLI construction and Serve usage. What are the precautions for Angular CLI construction and Serve usage? Here are practical cases, let’s take a look.

Build.

Build will mainly do the following actions:

1. Compile the project file and output it Go to a certain directory

2. Build targets determine the output result

3. bundling packaging

4. Production The build of the environment will also perform uglify and tree-shaking (removing useless code)

ng build.

You can read the help first :

ng build --help

For the development environment, use the command ng build.

By default, its output directory is configured in the ourDir attribute in the .angular-cli.json file, and the default is /dist Directory.

After building, you will see these files in dist:

1. inline.bundle.js This is the runtime of webpack.

2. main.bundle.js is the program code.

3. pollyfills.bundle.js is the browser’s Pollyfills.

4. styles. bundle.js style

5. vendor.bundle.js is angular and third-party library

You can use source-map-explorer to analyze dependencies, And check which modules and classes are in the bundle.

First modify the code in the previous example:

Execute ng build:

You can see that these files are generated.

Format the index.html in dist and take a look:

You can see that itreferences the 5 generated js files.

Open main.bundle.js and you can see the code I wrote:

Run the program below: ng serve -o:

You can see that when ng serve, the above is loaded The file.

Because ng build is a development build, no optimization has been done, and the file is quite large.

Look at the file directory at this time, there is no dist directory:

So how are these files served?

This is because webpack is being served in memory at this time.

The following is Use source-map-explorer for analysis, firstinstall it:

npm install --save-dev source-map-explorer

Then execute ng build, then execute:

.\node_modules\.bin\source-map-explorer dist\main.bundle.js

The result will generate this graph:

Look at the situation of vendor.bundle:

.\node_modules\.bin\source-map-explorer dist\vendor.bundle.js

There are more things in it.

Build Targets and Environment.

Environment refers to which environment file to use:

And Targets is used to determine the project How files are optimized.

Look at the comparison between development and production builds.

	ng build	ng build --prod
Environment	environment.ts	environment..prod.ts
Cache	Only cache images referenced in css	All builds File
source maps	generated	not generated
How to process css	Global css output to js file	The generated css file
uglify	is not	Yes
Tree-Shaking	Do not remove useless code	Remove Useless code
AOT	is not	is
Bundling Packaging	is	is
--build-optimizer	No	Yes (with AOT and Angular5)
--named-chunks	Yes	No
--output-hashing	media	all

下面命令都是针对开发时的build, 它们的作用是一样的:

ng build
ng build --dev
ng build --dev -e=dev
ng build --target=development --environment=dev

下面则是生产build:

ng build --prod
ng build --prod -e=prod
ng build --target=production --environment=prod

其它常用的参数还有:

1. --sourcemap -sm 生成source map

2. --aot Ahead of Time编译

3. --watch -w Watch并rebuild

4. --environment -e Build环境

5. --target -t Build target

6. --dev 表示dev env和target

7. --prod 表示prod env和target

Production Build.

先使用--aot:

ng build --aot

使用aot之后可以看到 vendor.bundle的大小降了很多, 只有1.5m左右了.

执行aot会去掉一些程序执行不需要的代码, 例如angular的compiler这时就不在build输出的文件里了(可以使用source-map-explorer查看).

试试生产环境:

ng build --prod

可以看到所有的文件都非常小了, 并且没有vendor了(因为prod下--build-optimizer起作用所以vendor没有了, 但可以使用--vendor-chunk true给弄出来).

Serve.

ng serve. 已经一直在用了, 下面看看它常用的参数:

1. --open -o 打开默认浏览器

2. --port -p 端口

3. --live-reload -lr 发生变化时重新加载网页(默认开启的)

4. --ssl 使用https

5. --proxy-config -pc 代理配置

6. --prod 在内存中serve 生产模式build的文件

试试 --prod:

ng serve --prod

通过文件大小可以看出确实是prod build的.

ng eject.

为项目生成webpack配置和脚本.

执行该命令试试:

看看有哪些变化:

.angular-cli.json:

package.json:

命令脚本都变了

还多出来一个webpack.config.js文件:

为什么要这么做呢?

可以对项目更深入的配置....

这时运行程序就是 npm start了.

我还是把reject恢复回去吧, 使用git来恢复吧.

如果需要Serve 其他js/css/assets文件:

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