How to detect is argument jQuery object

Question

I want to create function that can be used either with Id or by passing jQuery object.

var $myVar = $('#myId');

myFunc($myVar);
myFunc('myId');

function myFunc(value)
{
    // check if value is jQuery or string
}

How can I detect what kind of argument was passed to the function?

Note! This question is not same. I don't want to pass selector string like #id.myClass. I want to pass the jQuery object like in the example.

A jQuery object is not a "jQuery selector"; it's an object. A selector is a string with CSS selector syntax. — Pointy
– Pointy, Commented May 23, 2012 at 14:00
If you want to detect a jQuery object, then the part of that post that says value instanceof of jQuery (le mans: detecting an instance of jQuery object) would be the answer. — Joseph
– Joseph, Commented May 23, 2012 at 14:01
Off the top of my head, just check if the variable is a string or an object? — David Thomas
– David Thomas, Commented May 23, 2012 at 14:01

Sirko · Accepted Answer · 2012-05-23 14:03:09Z

18

Use the typeof operator

if ( typeof value === 'string' ) {
  // it's a string
} else {
  // it's something else
}

Or to make really sure it's an instance of the jQuery object

if ( typeof value === 'string' ) {
  // it's a string
} else if ( value instanceof $) {
  // it's a jQuery object
} else {
  // something unwanted
}

answered May 23, 2012 at 14:03

Sirko

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2 Comments

Tx3 Over a year ago

At least quick tests show that 'value instanceof $' is working smoothly. This was the thing that I was looking for. Thanks!

btburton42 Over a year ago

I would promote the second part as that really does the trick excluding other vanilla objects.

Parth Thakkar · Accepted Answer · 2012-05-23 14:06:21Z

3

Every jquery object has a property jquery. This will fail, of course, if your object has jquery property...but you can have stricter checking if you want...

function(o) {
    if(typeof o == 'object' && o.jquery) // it's jquery object.
}

answered May 23, 2012 at 14:06

Parth Thakkar

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Comments

Marc · Accepted Answer · 2012-05-23 14:09:47Z

1

function myFunc(value)
{
   if (typeof value == "string") {
      //it's a string
   }
   else if (value != null && typeof value == "object"} {
      //it's an object (presumably jQuery object)
   }
   else {
      //it's null or something else
   }


}

edited May 23, 2012 at 14:09

answered May 23, 2012 at 14:04

Marc

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2 Comments

James Allardice Over a year ago

typeof value will never be null. Did you mean value != null?

Marc Over a year ago

@JamesAllardice, yep, that's what I meant. Fixed it. Thank you.

BenM · Accepted Answer · 2012-05-23 14:03:37Z

0

Would it not be sufficient to check the type of the argument?

function myfunc(arg)
{
    if(typeof arg == 'string')
    {

    }
    else if(typeof arg == 'object')
    {

    }  
}

Check this Fiddle.

answered May 23, 2012 at 14:03

BenM

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1 Comment

Marc Over a year ago

This doesn't consider null, which also has typeof = "object".

Ilya Shpakovsky · Accepted Answer · 2012-05-23 14:04:28Z

0

Try this:

function myFunc(value)
{
   if(typeof value === 'object') {
   }
   else{
   }
}

answered May 23, 2012 at 14:04

Ilya Shpakovsky

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Comments

Eva · Accepted Answer · 2012-05-23 14:06:38Z

0

Try using typeof, eg:

var $myVar = $('#myId');

myFunc($myVar);
myFunc('myId');

function myFunc( value ){
    // check if value is jQuery or string
    switch( typeof value ) {
        case 'object':
        // is object
        break;

        case 'string':
        // is string
        break;

        // etc etc.
    }
}

answered May 23, 2012 at 14:06

Eva

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Comments

raddrick · Accepted Answer · 2012-05-23 14:14:21Z

0

function myFunc(value)
{
  if(typeof(value) == 'string')
    //this is a string
  else if (value === jQuery)
    //this is jQuery
  else if (typeof(value) == 'object')
    //this is an object
}

NOTE: did this in the console:

> jQuery
function (a,b){return new e.fn.init(a,b,h)}
> var value = jQuery
undefined
> value
function (a,b){return new e.fn.init(a,b,h)}
> value === jQuery
true

edited May 23, 2012 at 14:14

answered May 23, 2012 at 14:04

raddrick

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3 Comments

Tx3 Over a year ago

value === jQuery gives false for jQuery object

James Allardice Over a year ago

value === jQuery will only be true for jQuery itself, not instances of it. You want the instanceof operator. @RGB - Note that typeof is an operator, not a function, so you don't need the parentheses (they won't cause any problems, but it can be clearer without them).

raddrick Over a year ago

uhh, yes it does.. :P but i see you have a solution :)

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