Reference Types in JavaScript

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function , date object are reference type.but when i change reference value it don't change for other variable?

JavaScript

var date = new Date();
var tyt = date;
date = new Date(); //change date,but don't change tyt

JavaScript

var fun = myfunction;
   var fun2 = fun;
   fun = myfunction2;//change fun,but don't change fun2

Posted 1-Feb-12 23:16pm

User 7427435

Updated 1-Feb-12 23:47pm

v3

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Manfred Rudolf Bihy · Accepted Answer · 2012-02-01T23:41:00

Solution 1

You got that a bit wrong :). The second date = new Date(); does not change the first instance created by var date = new Date();, but rather replaces it completely. Thus date is now pointing at (referencing) a new instance of the Date object while tyt is still pointing (referencing) the original instance.
What you are after is an example like this:

JavaScript

var date = new Date();
var tyt = date;
date.setFullYear(2020); // Now that is a change that will also affect tyt since the original instance which tyt also points at is changed

alert(date);
alert(tyt);

Regards,

Manfred

Posted 1-Feb-12 23:41pm

Manfred Rudolf Bihy

Updated 1-Feb-12 23:44pm

v3

Comments

[no name] 2-Feb-12 5:56am

thanks Manfred.

Manfred Rudolf Bihy 2-Feb-12 5:59am

Why a 4?

[no name] 2-Feb-12 6:02am

it isn't my vote,my vote is 5.

Manfred Rudolf Bihy 2-Feb-12 6:04am

In that case I aplogize and gratefully accept your vote! :)

[no name] 2-Feb-12 6:06am

:D