bind:clientWidth doesn't update for resizable element

[colah]

Describe the bug
<textarea bind:clientWidth> doesn't update clientWidth when textarea is resized by user.

To Reproduce
repl example

Expected behavior
On user resize of textarea, I expected the bound value to update. Instead, the values stay stuck at the initial size.

Severity
Low. This is easy to work around, it would just be cleaner if this worked. Or in the alternative, if the documentation made it clear this wouldn't work.

[colah]

Initial state is correct:

After user resize, it is incorrect:

[Prinzhorn]

These are "Block-level element bindings", textarea is not a block-level element. The current implementation cannot work for textarea, see:

#4233
#5524

But I think there should be a warning in this case.

As a workaround wrap the element, but I think you are already aware of that https://svelte.dev/repl/9883af1a955148f0a57ca9caefa59e61?version=3.35.0

[Valexr]

bind:this={node} > node.clientWidth...

[Prinzhorn]

bind:this={node} > node.clientWidth...

@Valexr maybe I misunderstand your comment, but this is not reactive. You'd have to poll it (e.g. using raf) which can be expensive because the browser might have to do layout every single time you access the clientWidth property even though the size rarely changes. That's the reason why solutions like this exist in the first place because polling is (usually) expensive.

[Valexr]

https://svelte.dev/repl/1c7c89b3a80c48708f0f07720fb37a53

[colah]

D'oh, I thought "block element" referred to the CSS display property, rather than something else.

It would be nice if svelte emitted error messages when a user binds to an element that svelte doesn't support that type of binding to.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[Rich-Harris]

Svelte 5 uses resize observers meaning this works perfectly, so I'll close this