Updating multiple mongoDB collections from node js

Question

I am trying to update two seperate collections in a mongoDB database using mongoose and node.js. But I am getting an error for setting headers after they are sent.

The code that is being used to set this up is :

Line 170 is the line where customer.update is written

Mykola Borysyuk · Accepted Answer · 2016-10-01 14:13:16Z

3

You trying to send response two times after customer and admin collection update. That's why you got this error.

To solve this. Use async library http://caolan.github.io/async/docs.html#.parallel

Or custom functions with callbacks and only send headers when all collections got updated.

here is example

async.parallel([
   adminName: function(callback) {
      admin.update({yourUpdateCode}, function(err, AdminDoc){
         //you may want to add error handling here
         callback(null, AdminDoc);
      });
   },
   customerName: function(callback) {
      customer.update({yourUpdateCode}, function(err,doc){
       //you may want to add error handling here
        callback(null, CustDoc);
      });
   }],
function(err, results) {
   // results is now equals to: {adminName: AdminDoc, customerName: CustDoc}
   //your final callback here.
});

Hope this helps.

edited Oct 1, 2016 at 14:13

answered Oct 1, 2016 at 13:52

Mykola Borysyuk

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10 Comments

Nimit Bedi Over a year ago

Do we need to install some specific npm package for this?

Mykola Borysyuk Over a year ago

Well..You can use async lib as give you reference to DOCS. You can use promises if you want. You also can create methods that will update each collection and return final result to main function. About ASYNC. Yes you need to install it using npm.

Nimit Bedi Over a year ago

ok. What is the collName referring to in your inital snippet?

Mykola Borysyuk Over a year ago

Async each iterates over array of values and pass each value to callback function..Let me change example. So you understand better

Nimit Bedi Over a year ago

Ya that will be great

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