[csswg-drafts] Pull Request: [css-view-transitions-1] Clarify how unhandled rejections should work

jakearchibald has just submitted a new pull request for https://github.com/w3c/csswg-drafts:

== [css-view-transitions-1] Clarify how unhandled rejections should work ==
@domenic I'd like your feedback on this, as I'm not sure if this is the correct way to spec this.

Right now, in Chrome, this is a silent failure:

```js
const transition = document.startViewTransition(() => {
  doesNotExist();
});
```

…which is bad. Whereas:

```js
const transition = document.startViewTransition(() => {
  doesNotExist();
});

transition.updateCallbackDone;
transition.ready;
transition.finished;
```

…causes three unhandled rejections. That seems correct.

So, I want to spec that in the first example, there should still be one unhandled rejection, without creating four unhandled rejections in the second example.

I've tried to do this by creating only one unhandled promise when the `ViewTransition` instance is created (`transition.updateCallbackDone`). The other promises are handled, and only create unhandled promises when their properties are accessed.

Am I doing this right?

See https://github.com/w3c/csswg-drafts/pull/8451


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Received on Tuesday, 14 February 2023 14:12:26 UTC