5.Promise

5-1创建Promise对象

promise函数中传递两个参数
resolve —>处理成功 then去触发resolve
reject —>处理失败 catch去触发reject

//创建Promise对象
promise函数中传递两个参数
 resolve -->处理成功
 reject  -->处理失败
const p=new Promise(function(resolve,reject){
    //成功
 // let data="成功了"
 // resolve(data);
   //失败
  let data="失败了"
  reject(data)
})
//调用Promise then方法
p.then(fuction(value){
        console.log(value)       
},functiom(reason){
       console.log(reson)
})

5-2封装ajax

function http(url){
    return new Promise((resolve,reject)=>{
      $.ajax({
        url,
        success:res=>{
              resolve(res)
        },
        error:err=>{
            reject(err)
        }
  })
    })
    }

        var url=`http://47.108.197.28:3000/top/playlist`;
       http(url).then(function(res){
       console.log(res);
   })

5-3封装http

var baseUrl='http://47.108.197.28:3000'
function http(url){
 return new Promise((resolve,reject)=>{
  wx-wx.request({
    url:baseUrl+url,
    success: res => {
      resolve(res)
    },
    fail: (err) => {
      reject(err)
    },
  })
 })
}
function getMvHttp(){
  return http("/mv/first")
}
function getMvDetailHttp(id){
  return http(`mv/url?id=${id}`)
}
module.exports={
  getMvHttp,
  getMvDetailHttp
}