Performant variable declaration (based on DB document)

I have a question for all of the JS and Meteor experts on here.

I realized today that all throughout my app I reference a DB document as follows:

//define a const from the db
const usr = Meteor.users().findOne(id);
//and then create an object based off of the fields on the document
const userObj = {
  name: usr.fn,
  picture: usr.pic

So I was realizing that the usr that was defined inhereted ALL of the properties of the DB document, when I only used TWO of the properties to define my userObj.

My question is: would it be much more performant if i specified fields in query of the usr declaration? Or does it not make much of a difference?

I would basically change it to this:

const usr = Meteor.users.findOne(id, {fields: {fn: 1, pic: 1}});

I am sure it would help somewhat, but would it be worth it for me to go back through every declaration like this and “optimize” it with fields?? I really don’t know how expensive defining a variable with a large object is.

Thanks in advance :slight_smile: