returning an object from a javascript function

Question

I am trying to add a instance inside a function in javscript where i have observed the following behavior

function Calculator () {
    this.mm = 66;
    return 2 ;
}

var calculator = new Calculator();
console.log('  --> '+calculator.mm);   <<< gives output of 66

But the below code

function Calculator () {
    this.mm = 66;
    return {} ;
}

var calculator = new Calculator();
console.log('  --> '+calculator.mm);   <<< gives me undefined

I just want to know what different does returning an object from a primitive datatype make to a function . In other words why am i getting undefined here and not 66.

http://www.bennadel.com/blog/2522-providing-a-return-value-in-a-javascript-constructor.htm — demo, May 05 '16 at 15:00
You are returning an empty object which doesn't have a property of mm. Return 'this' instead. — NOBrien, May 05 '16 at 15:01

score -2 · Answer 1 · answered May 05 '16 at 14:59

-2

you should return the variable mm in the second one. Like return mm; That should solve your problem. Since you are not returning anything in the second one, that is why it is coming back as undefined.

answered May 05 '16 at 14:59

adam.v

1
2

function Calculator () { this.mm = 66; return {k:'aaa'} ; } even this gives me undefined while trying to access 'mm' – jayanthCoder May 05 '16 at 15:01
why are you doing that? Just do return mm; - That's all you need to do. – adam.v May 05 '16 at 15:10

returning an object from a javascript function

1 Answers1