CODEWITHSUNDEEP
javascriptnode.jsasync.js
nobinobiru
nobinobiru

Reputation: 792

async.js return last value when use waterfall method

all. I'm using asyncjs's waterflow method to return res value at last.But following code is return undefined value.

var async = require("async");
User.findBy = function(name,password){
  async.waterfall([
      function fetch(callback){
        db.lrange("users",0,-1,function(err,users){
          users.forEach(function(item){
            var u = JSON.parse(item);
            if ((u.name == name) && (u.password == password)){
              console.log(u);
              callback(null,u);
              return;
            }
          });
        });
        callback(null);
      }
      ],function end(err,res){

        setTimeout(function(){
        // I want to return res value at last.
        return u;
        },0);
      });
};

app.js

 // but it returns undefined value.
 var user = User.findBy("nobinobiru",a");

Do you have any idea? Please any help. Thanks in advance.

Upvotes: 1

Views: 2822

Answers (1)

Vadim Baryshev
Vadim Baryshev

Reputation: 26199

In fetch function you calling callback(null); immediately after the db.lrange call. This call unnecessary here, because you need to wait results from db.

This code should work fine:

var async = require("async");
User.findBy = function(name,password){
    async.waterfall([
        function fetch(callback){
            db.lrange("users",0,-1,function(err,users){
                var user;
                if (users && users.length) {
                    users.forEach(function(item){
                        var u = JSON.parse(item);
                        if ((u.name == name) && (u.password == password)){
                            console.log(u);
                            user = u;
                            return;
                        }
                    });
                    callback(null,user);
                } else {
                    callback(null);
                }
            });
        }
    ],function end(err,res){

        setTimeout(function(){
            // I want to return res value at last.
            return res;
        },0);
    });
};

Upvotes: 1

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