Excellent explanations. Makes sense. Thanks Jens.
On Thursday, 31 July 2025 at 7:25:56 pm UTC+10 Jens wrote:
> What I don't understand is why onload and onerror need a return value? I
> just return null as I've no clue what the return value should be.
>
>
> Because these on<Event> properties and their functions are defined that
> way. For example in the old days you could return false in an onclick
> function to suppress the click default action of the browser. These days it
> is recommended to always use addEventListener() instead of these event
> properties and to suppress the default action you call
> event.preventDefault().
>
> Also in JS a function basically always have some return value, e.g.
>
> function() {
> return;
> return undefined;
> // no return statement at all
> }
>
> is all the same and returns undefined. That is why Promises in elemental2
> also feel a bit clunky compared to JS. Promises allow you to return a new
> Promise/thenable in your success/catch callback methods so elemental2 has
> to define a return type for these callback functions. If you do not want to
> return a Promise/thenable in JS then you simply do not write a return
> statement but in Java you now have to write return null.
>
> -- J.
>
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