CODEWITHSUNDEEP
node.js
Chandra Prasad Mishra
Chandra Prasad Mishra

Reputation: 23

How to fix mongoose populating in Nodejs api by using async-waterfall?

I am novice in nodejs and I want to populate the data using async-waterfall. Can anyone help me to fix the error of below code? I don't know where the actually error is occuring. It might be either in API or in model to referencing the object id.

API

router.get('/restaurentdetails',(req,res)=>{
      waterfall([

          function(callback){
            var fk_user = Menu.fk_user;
            Owner.find().then((ownerInfo)=>{
                res.json(ownerInfo);
            }).catch(err =>{
                if(err){
                    throw err;
                }
            }); 
            callback(null,fk_user); 
        },
        function(fk_user,callback){
            Menu.find(fk_user).then((menuInfo)=>{
                res.json(menuInfo);
            }).catch(err =>{
                if(err){
                    throw err;
                }

            });
            //callback(null,'end');
        }
    ]),
    function(err,result){
        console.log('Main callback '+result);
    }

});

model1:-Owner detail model

const mongoose = require('mongoose');
const ownerSchema = new mongoose.Schema({
  name: {
    type: String,
    required: true
  },
  phone: {
    type: Number,
    required: true
  },
  email: {
    type: String,
    required: true
  },
});

module.exports = mongoose.model('ownerInfo', ownerSchema);

model2:-menu detail model

const mongoose = require('mongoose');
const menuSchema = new mongoose.Schema({
  fk_user: [{
    type: mongoose.Schema.Types.ObjectId,
    ref: 'ownerInfo'
  }],
  name: {
    type: String,
    required: true
  },
  price: {
    type: Number,
    required: true
  }
});

module.exports = mongoose.model('menuInfo', menuSchema);

I am getting the following error:-

(node:6456) UnhandledPromiseRejectionWarning: Error 
[ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the client
at ServerResponse.setHeader (_http_outgoing.js:470:11)
at ServerResponse.header (A:\nodejs 
 demo\RestaurantNew\node_modules\express\lib\response.js:767:10)
  at ServerResponse.json (A:\nodejs 
demo\RestaurantNew\node_modules\express\lib\response.js:264:10)
at Menu.find.then (A:\nodejs 
demo\RestaurantNew\controller\hotelController.js:59:21)
at process._tickCallback (internal/process/next_tick.js:68:7)
 (node:6456) UnhandledPromiseRejectionWarning: Unhandled promise 
rejection. This error originated either by throwing inside of an async 
function without a catch block, or by rejecting a promise which was not 
handled with .catch(). (rejection id: 1)
(node:6456) [DEP0018] DeprecationWarning: Unhandled promise rejections 
are deprecated. In the future, promise rejections that are not handled 
will terminate the Node.js process with a non-zero exit code.

Upvotes: 1

Views: 66

Answers (1)

Sathiraumesh
Sathiraumesh

Reputation: 6117

The problem is you are trying to send two responses for the same request here in the waterfall method first response is sent res.json(ownerInfo); and for the same request you call res.json(menuInfo); in the second function again What happens is that you are trying to send a response after it has already been sent. Try to send the result in only one function.

Upvotes: 1

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