Meteor Autoform `this.field("keyName").value` returns undefined in Schema

Question

I have a Person and I want a fullName field and value to automatically be created when a person changes their firstName or lastName fields.

People.attachSchema(new SimpleSchema({
    firstName: {
        type: String,
        optional: false,
        label: 'First Name'
    },
    lastName: {
        type: String,
        optional: false,
        label: 'Last Name'
    },
    fullName: {
        type: String,
        optional: false,
        label: 'Full Name',
        autoValue: function() {
          var firstName = this.field("firstName");
          var lastName = this.field("lastName");

          if(firstName.isSet || lastName.isSet){
                return firstName.value + " " + lastName.value;
            } else {
                this.unset();
            }
          }
    }
}));

If I then do

People.update("ZqvBYDmrkMGgueihX", {$set: {firstName: "Bill"}})

The fullName is set as Bill undefined

What am I doing wrong?

Answer 1

Right now, your condition firstName.isSet || lastName.isSet says, if either of firstName or lastName is available in the document, then create fullName. So it is correctly assigning full name, as one of them is set (First Name is set to Bill). You need to use && instead of || like this.

People.attachSchema(new SimpleSchema({
    firstName: {
        type: String,
        optional: false,
        label: 'First Name'
    },
    lastName: {
        type: String,
        optional: false,
        label: 'Last Name'
    },
    fullName: {
        type: String,
        optional: false,
        label: 'Full Name',
        autoValue: function() {
            var firstName = this.field("firstName");
            var lastName = this.field("lastName");

            if(firstName.isSet && lastName.isSet){
                return firstName.value + " " + lastName.value;
            } else {
                this.unset();
            }
        }
    }
}));

But, based on your question, I think, you want to set fullName only when one of firstName or lastName is updated then, I think (I am not sure), you need to check this.field('firstName').operator to check whether it is $set in the current operation or not.