async clipboard article does cover Chrome's use of Promise

[fergald]

Describe the bug

Chrome now supports writiing a Promise to the clipboard. The current docs only mention that for WebKit (at the bottom of the section on "write" .

It seems like synchronously setting a promise is the better way to do async clipboard copy. By using an async event handler, you risk overwriting an entry in the clipboard that was set before your async handler completed.

E.g. if the async handler waits for some other async event (e.g. a network request) before setting the clipboard, the clipboard could have been updated already.

[tomayac]

@fergald Thanks, tackled in #9816. In practice, I found the requirement to know the MIME type of the item beforehand limiting in some cases. Example:

// This randomly returns an `image/gif` or an `image/png` image.
const imgURL = '/images/random/';
await navigator.clipboard.write([
  new ClipboardItem({
    // This will be wrong when the returned image is an `image/gif`.
    'image/png': fetch(imgURL).then(response => response.blob()),
  })
]);

[fergald]

Thanks. That's a good point about mime types. I'm looking at this just because of this proposal for lazy generation of data only when the paste occurs. If they're tweaking the API, there might be an opportunity to address that .