set field as empty for mongo object using mongoose

问题:

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?

回答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();

回答2:

Does it make a difference if you try the set method instead, like this:

user.set('first_name', null);
user.set('signup_date', null);
user.save();

Or maybe there's an error when saving, what happens if you do:

user.save(function (err) {
    if (err) console.log(err);
});

Does it print anything to the log?

回答3:

Just delete fields

delete user.first_name;
delete user.signup_date;
user.save();

回答4:

Another option is to define a default value as undefined for these properties.

Something like the following:

let userSchema = new mongoose.Schema({ first_name: { type: String, default: undefined }, signup_date: { type: Date, default: undefined } })