Undefined returned when object method called

Asked Jul 26 '14 at 21:21

Active Jul 26 '14 at 21:21

Viewed 40 times

I create an object in the Chrome console with a function to increase the age. When I try and increase the age, I get "undefined" but I'm not sure why. Below is what I type into the console. As you can see the last line says undefined but it should say 41. Any thoughts?

>>obj = {}
Object {}
>>obj.firstName='John'
"John"
>>obj.lastName='Soro'
"Soro"
>>obj.age=40
40
>>obj.increaseAge = function() {
this.age++;
}
function () {
this.age++;
}
>>obj.lastName
"Soro"
>>obj.firstName
"John"
obj.increaseAge
function () {
this.age++;
}
obj.increaseAge()
undefined

asked Jul 26 '14 at 21:21

JustMe

5

This is the _return value_ of the function. In JavaScript all functions return `undefined` by default unless you have an explicit `return` statement. – Benjamin Gruenbaum Jul 26 '14 at 21:22
How do I get the method to work and return 41 – JustMe Jul 26 '14 at 22:58
@Isaac You must `return`: `obj.increaseAge = function() { return this.age++; }` – Oriol Jul 26 '14 at 23:00
@Oriol - I think you mean: `obj.increaseAge = function() { return ++this.age; }` – Jared Farrish Jul 26 '14 at 23:24

Undefined returned when object method called

0 Answers0