Question

I’m learning how to use Mootools’ Class, and I am trying to figure out how to detect whether a passed in element is just a single element (for example, $('foo')), or an Elements instance (e.g. $$('.class')).

I attempted to use typeOf, but both examples return me the type “object”.

I am aware that many Mootools functions can apply to both an Element instance and an Elements instance, but my class needs to know what it is receiving, or else it won’t know to iterate through all passed in elements, for example.

Is there a way I can differentiate between the two?

Answer 1

The typeOf function in mootools should be adequate, I would suggest you check your code to make sure the problem isn’t somewhere else. That said, you can also check for the existence of the ‘each’ function, which is a part of the array prototype extended by mootools:

<div class="myClass"></div>
<div class="myClass"></div>
<div class="myClass"></div>
<div class="myClass"></div>

<div id="myId"></div>

console.log(typeof $$('.myClass').each); // function
console.log(typeof $('myId').each); // undefined

However, the mootools function typeOf (docs: http://mootools.net/docs/core/Core/Core#Core:typeOf) should be giving you the best information. Be sure you aren’t using javascript’s built-in operator typeof (which I did use in the example above), but the moootools function typeOf as follows:

console.log(typeOf($$('.myClass'))); // elements
console.log(typeOf($('myId'))); // element

See it here: http://jsfiddle.net/49DwN/

Also note, the typeOf return for a group of elements is “element*s*”, where a single element is “element” – note the “s” there. Javascript’s typeof operator would return “object” for both cases.