when to use function() , function or () => function(callback)

Question

I have been searching for a while for a good explanation so its all clear to me. Example:

this.onDeleteHandler(index)}/>

Answer 1

this.onDeleteHandler(index)}/>

It passes anonymous function as a callback which - when clicked - triggers onDeleteHandler with extra index parameter (which has to be defined in the scope before).

It passes result of onDeleteHandler() as a callback - probably a bad idea - onDeleteHandler function has to return another function that will be invoked on click.

 this.nameChangedhandler(event, person.id)} />

Looks invalid - will result with syntax error.

Similar to the first example but doesn't take custom parameters. Default click event will be passed as a first argument for onDeleteHandler