As last stage of my pipeline, I have a $project like this :
{
...
anId : new ObjectId()
}
But mongo is generating the same Id for each document. I want it to generate a new different Id for each projected document. How to do so within the pipeline?
you can do it with the help of $function aggregation:
{
anId: {
$function: {
body: function() {
return new ObjectId();
},
args: [],
lang: 'js'
}
}
}