Question

I am able to $push an object onto a Mongo array as follows:

db.foo.update({},{$push:{bar:3}})

But I can’t find a syntax that will allow me to $pop the last item from the list.

I’ve tried things like:

db.foo.find({$pop:{bar:1}})

which does nothing. I’ve also tried

db.foo.find({id:23},{$pop:{bar:1}})  

which outputs:

error: { "$err" : "Unsupported projection option: bar", "code" : 13097 } 

Any ideas?

Answer 1

$pop exists and works almost like you’ve got it there, but you need to find some elements first!

db.foo.update({ _id: someId }, { $pop: { bar:1 } });

See the docs.