npm init -y
npm i -S koa@2

创建app.js文件,代码如下:

const Koa = require('koa')
const app = new Koa()

app.use(async (ctx,next) => {
    const start = new Date()
    console.log('[logger middleware] before await ...')
    await next()
    console.log('[logger middleware] after await ...')
    const ms = new Date() - start
    console.log(`${ctx.method} ${ctx.url} - ${ms}ms`)
})

app.use(async ctx =>{
    console.log('[response middleware] response ...')
    ctx.body = 'Hello Koa 2'
})

app.listen(3000)

koa V1 和 koa V2的用法差异

koa V1

var koa = requier('koa');
var app = koa();

koa V2

const Koa = require('koa');
const app = new Koa();

Koa脚手架 koa-generator

npm i --global koa-generator

利用koa-generator创建项目

koa2 helloworld    

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标签: node, 狼叔node.js web应用开发

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