set field as empty for mongo object using mongoose

Question

I'm calling user.save() on an object, where I set user.signup_date = null;

user.first_name = null; user.signup_date = null;  user.save(); 

But when I look at the user in the mongodb it still has the signup_date and first_name set...how do I effectively set this field as empty or null?

Answer 1

To remove those properties from your existing doc, set them to undefined instead of null before saving the doc:

user.first_name = undefined; user.signup_date = undefined;  user.save(); 

Confirmed as still working in Mongoose 5.9.7. Note that the field you're trying to remove must still be defined in your schema for this to work.