说明: 这篇文章并不是教大家如何用和如何写设计模式,而是给大家一个参考:如何搭建一个练习的ts版设计模式库

TypeScript版设计模式

js 的设计模式是经常使用的,但是最近在转 ts,所以就打算用 ts 重写 js 的设计模式. 说是重写其实也是模仿.

主要技术点: webpack + typescrpt + jest + ts-jest

使用 jest 测试的原因是使用和配置相对简单,并且支持 ts 文件(不需要编译成 js 文件后测试),也是 react 的推荐测试框架(毕竟 facebook 自己产品).

好了开始我们的旅程.

创建 package.json 文件及配置

npm init

如下:

{
  "name": "ts-design-pattern",
  "version": "1.0.0",
  "description": "ts design pattern",
  "main": "index.js",
  "scripts": {},
  "keywords": ["ts", "design", "pattern"],
  "author": "wwmin",
  "license": "ISC",
  "devDependencies": {}
}

更多配置请查看npm init

安装依赖

cnpm i typescript jest ts-jest @types/jest --save-dev

并设置 script 后 package.json 文件如下:

{
  "name": "ts-design-pattern",
  "version": "1.0.0",
  "description": "ts design pattern",
  "main": "index.js",
  "scripts": {
    "test": "jest"
  },
  "keywords": ["ts", "design", "pattern"],
  "author": "wwmin",
  "license": "ISC",
  "devDependencies": {
    "@types/jest": "^23.3.10",
    "jest": "^23.6.0",
    "ts-jest": "^23.10.5",
    "typescript": "^3.2.1"
  }
}

配置 typescript

tsc --init

后生成 tsconfig.json 文件内容如下

{
  "compilerOptions": {
    "target": "es2015",
    "module": "commonjs",
    "strict": true,
    "noImplicitAny": true
  }
}

更多配置请查看tsconfig.json

配置 jest

npx ts-jest config:init

后生成 jest.test.js 文件内容如下

module.exports = {
  preset: 'ts-jest',
  testEnvironment: 'node',
};

更多配置请查看ts-jest

创建文件夹及文件

|   .gitignore
|   jest.config.js
|   package.json
|   README.md
|   tsconfig.json
|
+---src
|       Adapter.ts
|
\---test
        Adapter.test.ts

整体文件夹结构大致就是这样, 这里也把.gitignore 内容放上,方便大家参考

.DS_Store
node_modules/
/dist/
npm-debug.log*
yarn-debug.log*
yarn-error.log*

# Editor directories and files
.idea
.vscode
*.suo
*.ntvs*
*.njsproj
*.sln
*.map

src 下和 test 的文件是完成的代码

创建第一个设计模式 adapter

在 src 下新建 Adapter.ts

代码如下:

interface MediaPlayer {
  play(type: string, fileName: string): void;
}

interface AdvanceMediaPlayer {
  playVlc?(fileName: string): void;
  playMp4?(fileName: string): void;
}

class VlcPlayer implements AdvanceMediaPlayer {
  playVlc(fileName: string) {
    console.log("playing vlc file......." + fileName);
  }
}

class Mp4Player implements AdvanceMediaPlayer {
  playMp4(fileName: string) {
    console.log("playing mp4 file......." + fileName);
  }
}

class MediaAdapter implements MediaPlayer {
  player: AdvanceMediaPlayer;
  constructor(type: string) {
    // 根据type 生成哪一个播放类
    if (type === "vlc") {
      this.player = new VlcPlayer();
    } else if (type === "mp4") {
      this.player = new Mp4Player();
    } else {
      this.player = new Mp4Player(); // 默认使用mp4player
    }
  }
  play(type: string, fileName: string) {
    // 因为特定的播放类有特定的播放方法，所以还需要再根据type调用特定的播放类
    if (type === "vlc") {
      if (this.player.playVlc) this.player.playVlc(fileName);
    } else if (type === "mp4") {
      if (this.player.playMp4) this.player.playMp4(fileName);
    } else {
      return null;
    }
  }
}

export class AudioPlayer implements MediaPlayer {
  play(type: "mp3" | "mp4" | "vlc", fileName: string): boolean {
    if (type === "mp3") {
      console.log("播放器内置支持mp3, " + fileName + "已开始播放.");
      return true;
    } else if (type === "vlc" || type === "mp4") {
      let ma = new MediaAdapter(type);
      ma.play(type, fileName);
      return true;
    } else {
      console.log("不支持当前格式");
      return false;
    }
  }
}

然后创建测试文件在 test 文件夹下新建 Adapter.test.ts 内容如下:

import { AudioPlayer } from "../src/Adapter";
test("playing to be true", () => {
  let player = new AudioPlayer();
  expect(player.play("mp3", "aa.mp3")).toBe(true);
  expect(player.play("mp4", "bb.mp4")).toBe(true);
  expect(player.play("vlc", "cc.vlc")).toBe(true);
});

关于 jest 的使用请参考 jest

完成代码后开始测试

npm run test 或 npm test

内容如下

 PASS  test/Adapter.test.ts
  √ playing to be true (18ms)

  console.log src/Adapter.ts:49
    播放器内置支持mp3, aa.mp3已开始播放.

  console.log src/Adapter.ts:18
    playing mp4 file.......bb.mp4

  console.log src/Adapter.ts:12
    playing vlc file.......cc.vlc

Test Suites: 1 passed, 1 total
Tests:       1 passed, 1 total
Snapshots:   0 total
Time:        1.002s, estimated 2s
Ran all test suites.

可以看到绿色的 passed 字样,如果测试没有通过则会有红色的错误提示.

好了,这就完成了 ts 版的设计模式库的搭建,后面我也会继续将设计模式慢慢补充完整, 代码可以参考我的github https://github.com/wwmin/ts-design-pattern

wwmin / ts-design-pattern