koa基础操作（2）

1,安装 koa-router

npm install -S koa-router

2,修改index.js

const Koa=require('koa');
const Router=require('koa-router')
const app=new Koa();
const router=new Router()

router.get('/',ctx=>{
  console.log(ctx.request);
  ctx.body='Hello World!';
})

router.get('/api',ctx=>{
  console.log(ctx.request);
  ctx.body='Hello Api!';
})

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

app.listen(3000);

async/await 使用同步代码修改

const Koa=require('koa');
const Router=require('koa-router')
const app=new Koa();
const router=new Router()

router.get('/',ctx=>{
  console.log(ctx.request);
  ctx.body='Hello World!';
})

router.get('/api',ctx=>{
  console.log(ctx.request);
  ctx.body='Hello Api!';
})

router.get('/async',async (ctx)=>{
  let result=await new Promise((resolve => {
    setTimeout(function() {
      resolve('hello world 2s later')
    },2000)
  }))
  ctx.body=result;
})
app.use(router.routes())
   .use(router.allowedMethods())

app.listen(3000);

插件
koa-router
https://www.npmjs.com/package/koa-router

koa-body
实现文件上传
https://www.npmjs.com/package/koa-body

解决跨域问题
https://www.npmjs.com/package/@koa/cors

美化json
https://www.npmjs.com/package/koa-json