Make displayed Web errors more meaningful

[adamscott]

Updates the code to display an error to not only show the message, but the context as well.

Before	After

[Faless]

Looking good! Nicely spotted!

[patwork]

Are we ok with "??" https://caniuse.com/?search=%3F%3F

Without need for msg it could be even:

	function displayFailureNotice(err) {
		console.error(err);
		setStatusNotice(err.message ?? err);
		setStatusMode('notice');
		initializing = false;
	}

will it make a difference?

setStatusNotice(err.message || err);

💣 EDIT: setStatusNotice will not handle err properly if it is not a string (because of split('\n'))

[Faless]

Are we ok with "??" https://caniuse.com/?search=%3F%3F

Indeed, I missed that, what's the rationale for chaining to ???

[adamscott]

Are we ok with "??" https://caniuse.com/?search=%3F%3F

Indeed, I missed that, what's the rationale for chaining to ???

?? is the new standard to test if a value exists or not. In the code changed, if err.message === "", it will resort back to err even if "" is a valid message, all because "" is a falsy value (which the or tests). The nullish operator (which is pretty much supported by all browsers since 2020) tests only if it's nullish, not if it's falsy.

[patwork]

Ah yes, ?? is better in this case, because:

const err = { message: "" };
const msg = err.message ?? err;
console.log(msg); // Outputs: ""

and || will break setStatusNotice

const err = { message: "" };
const msg = err.message || err;
console.log(msg); // Outputs: { message: "" }

[adamscott]

@patwork @Faless I updated my code finally, to make sure that setStatusNotice() is well set. Maybe overkill, but it will work.

function displayFailureNotice(err) {
	console.error(err);
	if (err instanceof Error) {
		setStatusNotice(err.message);
	} else if (typeof err === 'string') {
		setStatusNotice(err);
	} else if (typeof err === 'object' && typeof err.toString === 'function') {
		setStatusNotice(err.toString());
	} else {
		setStatusNotice('An unknown error occured');
	}
	setStatusMode('notice');
	initializing = false;
}

[patwork]

I guess we can assume that err will be either string or Error().

This could potentially get us "[Object Object]" or similiar:

	} else if (typeof err === 'object' && typeof err.toString === 'function') {
		setStatusNotice(err.toString());

It is better to write right away that it is an unknown error.

a= new Promise(() => {});
typeof a;
"object"
a.toString();
"[object Promise]" 

[akien-mga]

Thanks!