Javascript methods

Question

function person(name, age) {
this.name= name;
this.age = age;
this.yearOfBirth = bornYear;
}
function bornYear() {
return 2016 - this.age;
}

in the above code we have this.yearOfBirth but i dont see it being defined beforehand or did i get it all wrong ??

Answer 1

'bornYear' is a function, so it should be with parentheses:
this.yearOfBirth = bornYear();
When the above statement is executed, it calls the function 'bornYear()', which returns the needed value to the caller, so 'yearOfBirth' is assigned to that value.