Why is trigger('click') the same as $('#test').trigger({ type : 'click' });?

I am new to JS and basically I am trying to delve more into JS events and understand events and objects better. I came across a small difficulty that I would like to ask you kind people.

I wanted to know weather trigger('click') is the same as trigger({type : 'click'})

Now I wrote the below function to understand the difference and confirm if they are both the same:

<script>
    $(document).ready(function(){

        var call_it = function() {          
            setTimeout(function() {
                $('#test').trigger({
                    type : 'click' 
                });
            } , 1500 );
        }

        call_it();

        $('#test').on('click' , function(){
                console.log('button clicked');
        });
    });
</script>

Fiddle HERE

now when you replace :

$('#test').trigger({
        type : 'click' 
    });

with:

$('#test').trigger('click' );

the click is still triggered, but I am still confused, HOW and WHY are they the same ?? HOW are they internally the same?

I know its a trick question , but I hope somebody can answer it.

Thank you.

Tenali.