如何在 async.each 内部具有 async.waterfall 的外部函数中调用 async.each

Question

我在 Node.JS

中有一个导出模块

exports.doSomethingImportant= function(req, res) {
var id = req.params.id;
Demo.findOne({'_id': id})
  .exec(function(err, demosReturned) {
    async.waterfall([
        function(outerCallBack){
          console.log("In the First Call Back");
          firstOrderFunction(demosReturned,outerCallBack);
        },
        function(x,outerCallBack){
           var y =3 
           var z = x*y;
           console.log("In the Second Call Back");
           outerCallBack(null,z);
        }
      ],function(err,z){
        if(err){
          console.log("Error is == " +err);
        }else{
          console.log("The Returned Value is == "+z);
        }
      });
});//End Demo.findOne
};

现在，我的 firstOrderfunction 又有 async.each 嵌入 async.waterfall

function fistOrderFunction(demosReturned,outerCallBack){
console.log("Called the External Function");


async.each(demosReturned.locations, function(location, innerCallBack) {
  console.log('Computing Location #');

    async.waterfall([
          function(internalCallBack){
             console.log("Computing Inner First Waterfall");
               a = 14;
              innternalCallBack(null,a);
          },
          function(a,internalCallBack){
              console.log("Computing Inner Second Waterfall");
               b =14;
               c = a*b;
              innternalBack(null,c)
          }
      ],function(err,c){
        if(err){
          console.log("Error is == " +err);
        }else{
             d = c;
             console.log("The Returned Value is == "+c);
             innerCallBack(null,d);
        }
    });//End Async.Waterfall
},function(err,d){
    if(err){enter code here
      console.log("The Error in Async.Each === " + err);
    }else{
      console.log("The Returned Value is Processed ");
      outerCallBack(null, d);
    }
}); //End Async.Each
}

我得到的输出是

In the First Call Back

Called the External Function

Computing Location #

Computing Location #

Computing Inner First Waterfall

Computing Inner First Waterfall

The Returned Value is Processed

In the Second Call Back

The Returned Value is == NaN

我希望一切都运行按以下顺序同步。

Call async.waterfall in exec call back of Demo.findone

Call the firstOrderFunction

Call async.each inside firstOrderFunction

Call async.waterfall inside async.each

Call the first callback function returning a=14.

Call the second callback function returning c =14*14 =196.

如何使用异步实现此目的？

提前致谢，对于这么长的问题深表歉意。

Answer 1

在async.waterfall() 结束时调用async.each() 的回调，在async.each() 结束时调用firstOrderFunction 的回调。这是修改后的代码：

function fistOrderFunction(demosReturned, callback){
  var ret = [];

  console.log("Called the External Function");
  async.each(demosReturned.locations, function(location, eachCb) {
    console.log('Computing Location #');

    async.waterfall([
        function(waterfallCb){
            console.log("Computing Inner First Waterfall");
            a = 14;
            waterfallCb(null,a);
        },
        function(a,waterfallCb){
            console.log("Computing Inner Second Waterfall");
            b =14;
            c = a*b;
            waterfallCb(null,c)
        }
    ],function(err,c){
        if(err){
            console.log("Error is == " +err);
            eachCb(err);
        }else{
            ret.push(c);
            console.log("The Returned Value is == "+c);
            eachCb(null);
        }
    });//End Async.Waterfall
  },function(err){
    if(err){
        console.log("The Error in Async.Each === " + err);
        callback(err, null);
    }else{
        console.log("The Returned Value is Processed ");
        callback(null, ret);
    }
  }); //End Async.Each
}

如何在 async.each 内部具有 async.waterfall 的外部函数中调用 async.each

How to call async.each in an external function having async.waterfall inside async.each

javascript

asynchronous

mongoose

node.js

express