npm install koa koa-router --save

npm install -g nodemon

const Koa = require('koa');

const Router = require('koa-router');

// 实例化koa

const app = new Koa();

const router = new Router();

// 路由

router.get('/', async (ctx) => {

  ctx.body = {

    msg: 'Hello Koa Interfaces'

  }

})

// 配置路由

app.use(router.routes()).use(router.allowedMethods());

// 设置端口号

const port = process.env.PORT || 5000;

// 监听端口号

app.listen(port, () => {

  console.log(`server started on ${port}`)

})

{

  "name": "koa_app",

  "version": "1.0.0",

  "description": "",

  "main": "app.js",

  "scripts": {

    "start": "node app.js",

    "nodemon": "nodemon app.js"

  },

  "keywords": [],

  "author": "",

  "license": "ISC",

  "dependencies": {

    "koa": "^2.7.0",

    "koa-router": "^7.4.0"

  }

}