在express中使用ES7装饰器构建路由

在Java的Spring框架中，我们经常会看到类似于@Controller这样的注解，这类代码能够极大的提高我们代码的可读性和复用性。而在Javascript的ES7提案中，有一种新的语法叫做decorator，它能够在Javascript中实现与注解相同的功能。

@tuzilow/express-decorator

@tuzilow/express-decorator是由本人开发的一个简单的express装饰器包，具有@Controller、@RootUrl、@Get等API，能够方便快捷的构建express后台接口。

正式开始

创建package.json

执行npm init，并使用npm或yarn添加以下依赖

{
  "name": "decorator-demo",
  "version": "1.0.0",
  "main": "index.js",
  "license": "MIT",
  "dependencies": {
    "@tuzilow/express-decorator": "^0.0.3",
    "express": "^4.17.1"
  },
  "devDependencies": {
    "@babel/cli": "^7.11.6",
    "@babel/core": "^7.0.0",
    "@babel/node": "^7.0.0",
    "@babel/plugin-proposal-class-properties": "^7.10.4",
    "@babel/plugin-proposal-decorators": "^7.10.5",
    "@babel/preset-env": "^7.0.0",
    "babel-eslint": "^9.0.0"
  },
  "scripts": {
    "start": "babel-node index"
  }
}

创建.babelrc

{
  "plugins": [
    ["@babel/plugin-proposal-decorators", { "legacy": true }],
    ["@babel/plugin-proposal-class-properties", { "loose": true }]
  ],
  "presets": ["@babel/preset-env"]
}

创建index.js并编写代码

首先，编写一个普通的express应用

import express from 'express';

const Server = express();

Server.get('/', (req, res) => {
  res.json({
    title: 'hello world',
  });
});

Server.listen(3000, () => {
  console.info('running in http://localhost:3000');
});

执行无误后使用@tuzilow/express-decorator对其进行改造

import express from 'express';
import { Controller, Get } from '@tuzilow/express-decorator';

const Server = express();

@Controller
class User {
  @Get('/')
  home(req, res) {
    res.json({
      title: 'hello world',
    });
  }
}

Server.use(new User());

Server.listen(3000, () => {
  console.info('running in http://localhost:3000');
});

运行结果与前面普通的express应用的运行结果相同，如果想要设定统一的父级路由，可以使用@RootUrl

import express from 'express';
import { Controller, Get, RootUrl } from '@tuzilow/express-decorator';

const Server = express();

@Controller
class User {
  @RootUrl('/user') url() {}
  
  @Get('/')
  home(req, res) {
    res.json({
      title: 'hello world',
    });
  }
   
  @Get('/list')
  list(req, res) {
    res.json({
      title: 'this is a list',
    });
  }
}

Server.use(new User());

Server.listen(3000, () => {
  console.info('running in http://localhost:3000');

这样请求路径就会变为http://localhost:3000/user和http://localhost:3000/user/list，因为该装饰器包只提供了简易的API，因此传递参数、设置header等操作需要使用express的方法

import express from 'express';
import { Controller, Get, RootUrl, Post } from '@tuzilow/express-decorator';

const Server = express();

@Controller
class User {
  @RootUrl('/user') url() {}

  @Get('/')
  home(req, res) {
    res.json({
      title: 'hello world',
    });
  }

  // query传参
  @Get('/getOne')
  getOne(req, res) {
    const { id } = req.query;
    res.json({
      title: 'hello world',
      id,
    });
  }

  // params传参
  @Get('/list/:id')
  getItem(req, res) {
    const { id } = req.params;
    res.json({
      title: 'hello world',
      id,
    });
  }

  // body传参
  @Post('/create')
  create(req, res) {
    const { id } = req.body;
    res.json({
      code: 0,
      id,
    });
  }
}

Server.use(new User());

Server.listen(3000, () => {
  console.info('running in http://localhost:3000');
});

项目源码

• GitHub仓库地址：Tuzilow/express-decorator
• npm地址：@tuzilow/express-decorator