[equality] jQuery object equality

How do I determine if two jQuery objects are equal? I would like to be able to search an array for a particular jQuery object.

$.inArray(jqobj, my_array);//-1    
alert($("#deviceTypeRoot") == $("#deviceTypeRoot"));//False
alert($("#deviceTypeRoot") === $("#deviceTypeRoot"));//False

This question is related to equality jquery

The answer is


The $.fn.equals(...) solution is probably the cleanest and most elegant one.

I have tried something quick and dirty like this:

JSON.stringify(a) == JSON.stringify(b)

It is probably expensive, but the comfortable thing is that it is implicitly recursive, while the elegant solution is not.

Just my 2 cents.


Use Underscore.js isEqual method http://underscorejs.org/#isEqual


It is, generally speaking, a bad idea to compare $(foo) with $(foo) as that is functionally equivalent to the following comparison:

<html>
<head>
<script language='javascript'>
    function foo(bar) {
        return ({ "object": bar });
    }

    $ = foo;

    if ( $("a") == $("a") ) {
        alert ("JS engine screw-up");
    }
    else {
        alert ("Expected result");
    }

</script>

</head>
</html>

Of course you would never expect "JS engine screw-up". I use "$" just to make it clear what jQuery is doing.

Whenever you call $("#foo") you are actually doing a jQuery("#foo") which returns a new object. So comparing them and expecting same object is not correct.

However what you CAN do may be is something like:

<html>
<head>
<script language='javascript'>
    function foo(bar) {
        return ({ "object": bar });
    }

    $ = foo;

    if ( $("a").object == $("a").object ) {
        alert ("Yep! Now it works");
    }
    else {
        alert ("This should not happen");
    }

</script>

</head>
</html>

So really you should perhaps compare the ID elements of the jQuery objects in your real program so something like

... 
$(someIdSelector).attr("id") == $(someOtherIdSelector).attr("id")

is more appropriate.


If you want to check contents are equal or not then just use JSON.stringify(obj)

Eg - var a ={key:val};

var b ={key:val};

JSON.stringify(a) == JSON.stringify(b) -----> If contents are same you gets true.


First order your object based on key using this function

function sortObject(o) {
    return Object.keys(o).sort().reduce((r, k) => (r[k] = o[k], r), {});
}

Then, compare the stringified version of your object, using this funtion

function isEqualObject(a,b){
    return JSON.stringify(sortObject(a)) == JSON.stringify(sortObject(b));
}

Here is an example

Assuming objects keys are ordered differently and are of the same values

var obj1 = {"hello":"hi","world":"earth"}
var obj2 = {"world":"earth","hello":"hi"}

isEqualObject(obj1,obj2);//returns true

If you still don't know, you can get back the original object by:

alert($("#deviceTypeRoot")[0] == $("#deviceTypeRoot")[0]); //True
alert($("#deviceTypeRoot")[0] === $("#deviceTypeRoot")[0]);//True

because $("#deviceTypeRoot") also returns an array of objects which the selector has selected.