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How Angular CLI implements Build

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php中世界最好的语言Original
2018-06-14 10:31:171643browse

This time I will show you how Angular CLI implements Build, and what are the precautions for Angular CLI to implement Build. The following is a practical case, 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 it references 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 the above file is loaded during ng serve.

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

Now look at the file directory, there is no dist directory:

So how are these files served?

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

Use source-map-explorer below To analyze, first install 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:

Let’s 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 is used:

And Targets is used to determine how the project file is optimized.

Look at the comparison between development and production builds.

##environment..prod.tsCacheOnly cache images referenced in cssAll build filessource mapsGenerateDo not generate How to process cssGlobal css output to js fileThe generated is css file##uglifyTree-ShakingAOTBundling Packaging--build-optimizer--named-chunks--output-hashing

ng build

##ng build --prod

Environment

environment.ts

not

is

Do not remove useless code

Remove useless code

No

is

is

is

No

##Yes (with AOT and Angular5)

Yes

No

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:

放在.angular-cli.json就行, 例如jquery就应该放在scripts里面.

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