Adding hours to JavaScript Date object?

Question

It amazes me that JavaScript\'s Date object does not implement an add function of any kind.

I simply want a function that can do this:

var now = Date         


        

Answer 1

It is probably better to make the addHours method immutable by returning a copy of the Date object rather than mutating its parameter.

Date.prototype.addHours= function(h){
    var copiedDate = new Date(this.getTime());
    copiedDate.setHours(copiedDate.getHours()+h);
    return copiedDate;
}

This way you can chain a bunch of method calls without worrying about state.