Setting object by value instead of reference

Question

I'm trying to init a var in JS with date from another JS object but whatever i am trying getting reference to the old object (pointer) and I need it not to change.

var lastActionDate = new Date(mainLastActionDate);
var nowDate = new Date();
var tmpLastActionDate = lastActionDate;

if ((tmpLastActionDate.setDate(tmpLastActionDate.getDate() + 7)) > nowDate)

The last line is the problematic line. I thought that lastActionDate should not be changed and i need it to stay with the old date, but it changes with tmpLastActionDate and i am guessing because it is a pointer.

How can one set a date object by value instead of reference?

Could you please post some code? I don't really understand what you're trying to achieve here... — Henrik Andersson, Apr 10 '12 at 08:24
Use a copy: `var tmpLastActionDate = new Date(lastActionDate);` — RobG, Apr 10 '12 at 09:07

score 2 · Accepted Answer · answered Apr 10 '12 at 08:24

2

Try this :

d=new Date()
e=new Date(d.valueOf())

answered Apr 10 '12 at 08:24

mpm

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So simple, thank you, in 5 minutes i will mark your answer as the correct one....so simple, valueOf, stupid me :-) – Erez Apr 10 '12 at 08:28
@camus—you can just do `e - new Date(d);`, no need for `valueOf` or `getTime`. – RobG Apr 10 '12 at 09:11
I Think I've tried that and didn't work, don't know why....but this one works, 10x – Erez Apr 10 '12 at 10:42

score 1 · Answer 2 · edited May 23 '17 at 11:56

1

You have to clone your original Date object. You can use this method :

var date = new Date();
var copiedDate = new Date(date.getTime());

Reference: How to clone a Date object in JavaScript

edited May 23 '17 at 11:56

Community

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answered Apr 10 '12 at 08:25

nicopico

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Setting object by value instead of reference

2 Answers2