如何获取js异步请求返回值-蒲公英云

如何获取js异步请求返回值

使用定时函数模拟异步请求

回调函数

function doSomething(callback){
    setTimeout(function(){
        console.log('执行结束');
        let result = 4;
        callback(result);
    },100);
}
function callback(result){
    console.log('接收到结果为：'+result);
}
doSomething(callback);
//doSomething((result)=>{console.log('接收到结果为：'+result)});

使用es6提供的Promise函数

function doSomething(){
    return new Promise(function(resolve){
        setTimeout(function(){
            console.log('执行结束');
            let result = 6;
            resolve(result);
        },100);
    });
}
doSomething().then(result=>{
    console.log('接收到结果为：'+result);
});

Generator函数

function doSomething(){
    setTimeout(function(){
        let result = 6;
        it.next(result);
    },100);
}
function *gener(){
    var result = yield doSomething();
    console.log(result);
}
let it = gener();
it.next();

使用es7新特性async

function doSomething(){
    return new Promise(resolve=>{
        setTimeout(function(){
            let result = 6;
            resolve(result);
        },100);             
    });
}
async function action(){
    let result = await doSomething();
    console.log(result);
}
action();