How to remove array element in mongodb?

Question

Try the following query:

collection.update(
  { _id: id },
  { $pull: { 'contact.phone': { number: '+1786543589455' } } }
);

It will find document with the given _id and remove the phone +1786543589455 from its contact.phone array.

You can use $unset to unset the value in the array (set it to null), but not to remove it completely.

This below code will remove the complete object element from the array, where the phone number is '+1786543589455'

db.collection.update(
  { _id: id },
  { $pull: { 'contact': { number: '+1786543589455' } } }
);

You can simply use $pull to remove a sub-document. The $pull operator removes from an existing array all instances of a value or values that match a specified condition.

Collection.update({
    _id: parentDocumentId
  }, {
    $pull: {
      subDocument: {
        _id: SubDocumentId
      }
    }
  });

This will find your parent document against given ID and then will remove the element from subDocument which matched the given criteria.

Read more about pull here.

In Mongoose: from the document:

To remove a document from a subdocument array we may pass an object with a matching _id.

contact.phone.pull({ _id: itemId }) // remove
contact.phone.pull(itemId); // this also works

See Leonid Beschastny's answer for the correct answer.