javascript - Node.js - 在另一个方法完全执行后调用一个方法

Question

我有两个简单的方法:

 function do(x,y){
   if(x){
    XHR1().success();
   }
   if(y){
    XHR2().success();
   }
}

function done(){
   return something;
}

现在我只想确保在 do() 完成时调用 done()(**do() 方法包含对Mysql数据库)

我怎样才能做到这一点？**

显然这不会按顺序放置这些方法:

do(x=1,y=1);

done(); //this can run also if do() has not finished yet

所以我尝试了:

function do(x,y,_callback){
       if(x){
        XHR1().success();
       }
       if(y){
        XHR2().success();
       }

      _callback();
    }

    function done(){
       return something;
    }

do(x=1,y=1,done()); // this won't work the same cause callback is not dependent by XHR response

这就是我用于 promise 的内容 https://github.com/tildeio/rsvp.js/#arrays-of-promises

Answer 1

i know about promises but i can't get how to put it in sintax

假设 XHR() 确实返回了一个 promise，那么您的代码应该是这样的:

function do(x,y) {
    var requests = [];
    if (x)
        requests.push( XHR1() );
    if (y)
        requests.push( XHR2() );
    return RSVP.all(requests);
}
function done(){
    return something;
}

do(1, 1).then(done);