场景需求：场景需求：需要同时请求5个接口都请求成功后执行下一步操作解决方法：解决方法：解决方法：定义一个变量i=5，请求成功一个接口，让i–，直到i=0时执行下一个操作，否则不执行axios.all 并发请求，.then(axios.spread(function(callback1, callback2)){})promise.all 并发请求，.then(function([callback1, callback2]){})1、回调地狱：1、回调地狱：函数作为参数层层嵌套代替的为.then的链式操作2、promise.all并发请求2、promise.all并发请求引入接口
import {getSellerDetail} from '../../api/seller'
import {getMemberCardInfo} from '../../api/pay_online/index'
import {getSellerDetail} from '../../api/seller'import {getMemberCardInfo} from '../../api/pay_online/index'数据处理1. 创建一个Promise实例，获取数据2. 并把数据传递给处理函数resolve和reject3. promise在声明时就执行了
created(){

if (this.$route.query.type){

this.type = this.$route.query.type;

this.sellerId = this.$route.query.targetId;

this.initApi()

}
},
methods: {

initApi(){

`// 商户信息`

let SellerDetailApi = new Promise((resolve, reject) => {

getSellerDetail(this.sellerId).then( res => {

resolve(res)
// resolve(res.data)

}).catch( err => {

reject(res)

})

})

`// 会员卡信息`

let MemberCardInfoApi = new Promise((resolve, reject) => {

getMemberCardInfo(this.sellerId, this.payMoney).then( res => {

resolve(res) // resolve(res.data)

}).catch( err => {

reject(res)

})

})

`// Promise的all方法，等数组中的所有promise对象都完成执行`

Promise.all([SellerDetailApi, MemberCardInfoApi]).then( res => {

this.loading = false;

// 商户信息

this.detail = res[0].data.detail;

this.sellerPic = this.detail.picture;

this.sellerName = this.detail.name;

this.discount = this.detail.discount;

// 会员卡信息

this.cardDetail = res[1].data;

this.balance = this.cardDetail.balance; //余额

this.rechargeTip = this.cardDetail.rechargeTip; // 付款金额提示充值

}).catch( err => {

console.log(err)

})

}
}
created(){

if (this.$route.query.type){

this.type = this.$route.query.type;

this.sellerId = this.$route.query.targetId;

this.initApi()

}
},
methods: {

initApi(){

`// 商户信息`

let SellerDetailApi = new Promise((resolve, reject) => {

getSellerDetail(this.sellerId).then( res => {

resolve(res)
// resolve(res.data)

}).catch( err => {

reject(res)

})

})

`// 会员卡信息`

let MemberCardInfoApi = new Promise((resolve, reject) => {

getMemberCardInfo(this.sellerId, this.payMoney).then( res => {

resolve(res) // resolve(res.data)

}).catch( err => {

reject(res)

})

})

`// Promise的all方法，等数组中的所有promise对象都完成执行`

Promise.all([SellerDetailApi, MemberCardInfoApi]).then( res => {

this.loading = false;

// 商户信息

this.detail = res[0].data.detail;

this.sellerPic = this.detail.picture;

this.sellerName = this.detail.name;

this.discount = this.detail.discount;

// 会员卡信息

this.cardDetail = res[1].data;

this.balance = this.cardDetail.balance; //余额

this.rechargeTip = this.cardDetail.rechargeTip; // 付款金额提示充值

}).catch( err => {

console.log(err)

})

}
}3、接口返回：3、接口返回：promise.all中console.log(res) 返回的是数组接口返回4、注意：4、注意：Promise.all 缺陷 如果其中某个任务出现异常(reject)，所有任务都会挂掉，Promise直接进入 reject 状态至catch回调。Promise.allSettled 无论一个任务正常或者异常，都会返回对应的的状态，可以解决上述问题补充知识：vue项目中Promise同步请求补充知识：补充知识：vue项目中Promise同步请求1.js中定义Promise1.js中定义Promise
export function wxLogin() {
let pResult = new Promise((resolve, reject) => {
uni.login({

provider: 'weixin',

success: (res) => {

console.log('login success:', res);

// return res;

setTimeout(function() {

resolve(res);

}, 3000);

},

fail: (err) => {

console.log('login fail:', err);

reject(err);

}
});
}).catch(res => {
console.log(666, res);
})
return pResult;
}
export function wxLogin() {
let pResult = new Promise((resolve, reject) => {
uni.login({

provider: 'weixin',

success: (res) => {

console.log('login success:', res);

// return res;

setTimeout(function() {

resolve(res);

}, 3000);

},

fail: (err) => {

console.log('login fail:', err);

reject(err);

}
});
}).catch(res => {
console.log(666, res);
})
return pResult;
}2.vue文件中使用2.vue文件中使用
import {login,wxLogin} from '@/common/login.js'


(async () => {

//获取授权状态

console.log(1111,"111")

let aaa = await wxLogin();

console.log(3333,"3333");

console.log(4444,aaa);

})()

import {login,wxLogin} from '@/common/login.js'


(async () => {

//获取授权状态

console.log(1111,"111")

let aaa = await wxLogin();

console.log(3333,"3333");

console.log(4444,aaa);

})()
以上这篇在vue项目中promise解决回调地狱和并发请求的问题就是小编分享给大家的全部内容了，希望能给大家一个参考。