How do I tell difference between object and string in javascript?

Question

I have a javscript function (actually a jQuery plugin) which I will want to call as either

myFunction("some input");

or

myFunction({ "prop": "value 1", "prop2": "value2" });

How do I, in the function, tell the two apart?

In other words, what should go in the if conditions below?

if (/* the input is a string */)
{
    // Handle string case (first of above)
}
else if (/* the input is an object */)
{
    // Handle object case (second of above)
}
else
{
    // Handle invalid input format
}

I have jQuery at my disposal.

Update: As noted in an answer, if the input is new String('some string') , typeof(input) will return 'object' . How do I test for new String('') , so I can handle that the same way as '' ?

Answer 1

if( typeof input === 'string' ) {
    // input is a string
}
else if( typeof input === 'object' ) {
    // input is an object
}
else {
    // input is something else
}

Note that typeof considers also arrays and null to be objects:

typeof null === 'object'
typeof [ 1, 2 ] === 'object'

If the distinction is important (you want only "actual" objects):

if( typeof input === 'string' ) {
    // input is a string
}
else if( input && typeof input === 'object' && !( input instanceof Array ) ) {
    // input is an object
}
else {
    // input is something else
}

Answer 2

jQuery.type may be interesting to you.

if($.type(input)==='string')
{
   //it's a string
}

Answer 3

As others have said, the typeof operator will determine the type of the variable.

Beware though:

var str = 'A String' ;
var obj = new String(str) ;
console.log(typeof str) ;
console.log(typeof obj) ;

// Outputs:
// string
// object

Answer 4

The typeof operator may get you what you need. ie:

typeof(myobj) == 'string'

(IIRC)

Answer 5

You can;

function f(a) { print(typeof a) }

f({"prop": "value 1", "prop2": "value2" });

>>object

f("Some input");

>>string

Answer 6

In javascript the command typeof returns the type of the variable.

I created a little jsfiddle It seems that the array returns also typeof as an object.

Answer 7

<script>
var a = {'a':'b'};
if(typeof(a) == 'object'){
    alert('object');
}
elseif(typeof(a) == 'string'){
    alert('string');
}
</script>

http://forums.devx.com/showthread.php?t=5280

Answer 8

You can use the typeof function:

if (typeof(myvar) === 'string') {
  // the code
}

see here for more information

Answer 9

You want to use $.type , as this is more accurate than typeof

$.fn.plugin = function( options ) {

    console.log( $.type( options ) );

    if( $.type( options ) == 'string' ) {
        // Handle string case (first of above)
    }
    else if( $.type( options ) == 'object' && options != null ) {
        // Handle object case (second of above)
    }
    else {
        // Handle invalid input format

    }

};

$("#d1").plugin( new String('test')); //string
$("#d1").plugin('test'); //string
$("#d1").plugin({'key' : 'value'}); //object

Demo here

Edit

Also if options is not set then !options would be sufficient