Node JS Mongoose update request inside for loop or foreach, is it possible?
I have two different objects inside an array and I want to use these objects to update the collection in my mongodb So although I am using something like this:
for (i = 0 ; i < array.length ; i++) {
Model.update({array[i]._id},{$set : {'credits_pending' : array[i].credits_pending}},false,true)
}
But it only updates the first value of my array, I mean array [0]
Why?
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First, updates (and most other operations) in Mongoose are asynchronous, so you need to wait for the operation to complete before continuing. It is usually best to do one operation at a time on one collection. With a loop, for
you are simultaneously performing two asynchronous operations on the same collection, which can lead to unwanted behavior.
Second, I think your Model.update () arguments are slightly off.
I like to use async.js when working with Mongoose, so below is an example of how you can update an array of objects one at a time.
var async = require('async');
async.eachSeries(array, function updateObject (obj, done) {
// Model.update(condition, doc, callback)
Model.update({ _id: obj._id }, { $set : { credits_pending: obj.credits_pending }}, done);
}, function allDone (err) {
// this will be called when all the updates are done or an error occurred during the iteration
});
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I don't know what your circuit looks like, but if this is the only way to do it, try something like -
//array - your original array
async.eachSeries(array, function(rec, callback) {
updateRecord(rec._id, rec.credits_pending)
.then((updated) => {
callback();
})
}, function(err){
//execution comes here when array is fully iterated.
});
function updateRecord(id, credits) {
return Model.update({array[i]._id},{$set : {'credits_pending' : array[i].credits_pending}});
}
Mongoose maintains promise internally, so you don't have to worry about anything else.
"Note" - to update several documents, you must select some property that is common to all documents. This approach is wrong and you must design a circuit to avoid such scenarios. This answer is in case you have no other choice.
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