How To Determine If Parameter Is An Array Or An Object In JavaScript?

I have a prototype like this; LocalDataEngine.prototype.ExecuteNonQuery = function (query) { } And I call this prototype within two different argument like below; By using object

Solution 1:

You can use instanceof:

% js
> [] instanceof Array
true
> {} instanceof Array
false

It will work flawlessly if you are not using frames (which is probably a bad idea anyway). If you are using frames and ECMAScript 5, use Array.isArray:

> Array.isArray({})
false
> Array.isArray([])
true

See the duplicate question linked by thg435 for additional solutions.

Solution 2:

Like this:

if (query instanceof Array) {
    return 'array';
} else if (query instanceof Object) {
    return 'object';
} else {
    return 'scalar';
}

Solution 3:

if( Object.prototype.toString.call( yourObj) === '[object Array]' ) {
    alert( 'Array!' );
}