Handling my object's casting to number

Question

As you all know there is a toString() method for object which is called whenever the casting is required.

I was wondering if there is such a method for casting to number (like the Date object in which +new Date() returns the getTime() method's value).

For example (let's say there is toNumber method):

function MyObj(){}
MyObj.prototype.toNumber = function(){
    return 1362;
}

Wait, `+new Date()` is magic and returns the timestamp? That's horrifying. — Alexis King, Jan 21 '15 at 06:12

score 3 · Accepted Answer · edited May 23 '17 at 11:43

3

Yes, it's called valueOf:

function MyObj(){}
MyObj.prototype.valueOf = function(){
    return 1362;
}

See also the second part of my answer here.

edited May 23 '17 at 11:43

Community

answered Jan 21 '15 at 06:12

Felix Kling

I honestly had no idea this was part of JavaScript, and I consider myself fairly well-versed in JS's oddities. – Alexis King Jan 21 '15 at 06:16

1 Answers1