Merge $lookup result to existing array

Question

I\'m new to mongo and I need your help.

I have collection studijneProgramy. This is sample document:

{
    \"_id\" : \"dGFY\",
    \         


        

Answer 1

Other than the potential duplicate pointed out by dege, you can use JS as follows if it isn't a lot of data. Using aggregate and $lookup would be faster, but this is cleaner, I believe.

db.studijneProgramy.find().forEach(stu=>{
    stu.garranti=stu.garranti.map(gar=>{
        gar.garant=db.osoby.find({_id:gar.id})[0];
        return gar;
    });
    db.studijneProgramy.save(stu);
});