Issue with VSCode Incorrectly Reporting bind:clientWidth as an Error

[MineYuanlu]

Describe the bug

I followed the documentation (https://svelte.dev/docs/svelte/bind#Function-bindings) to write code using bind:clientWidth, but I encountered an error:

Object literal may only specify known properties, and '"bind:clientWidth"' does not exist in type 'HTMLProps<"div", HTMLAttributes<any>>'.ts(2353)

However, if I ignore the error reported by VSCode, the page works as expected.

Additionally, I noticed that the following code works fine:

<div bind:clientWidth={w}>content</div>

But when I use it like this, it doesn't work:

<div bind:clientWidth={null, (v) => w=v}>content</div>

Version:

• VSCode: 1.98.2 (Universal)
• svelte.svelte-vscode: 109.5.3 (2025-03-06, 23:40:48)

Reproduction

<script lang="ts"> let w=$state(0); </script>

w=v}>content

Logs

System Info

System:
    OS: macOS 14.0
    CPU: (10) arm64 Apple M1 Pro
    Memory: 87.77 MB / 16.00 GB
    Shell: 5.2.32 - /opt/homebrew/bin/bash
  Binaries:
    Node: 20.17.0 - ~/.nvm/versions/node/v20.17.0/bin/node
    npm: 11.0.0 - ~/.nvm/versions/node/v20.17.0/bin/npm
    pnpm: 9.15.1 - ~/.nvm/versions/node/v20.17.0/bin/pnpm
  Browsers:
    Chrome: 135.0.7049.42
    Safari: 17.0
  npmPackages:
    svelte: ^5.0.0 => 5.25.3

Severity

annoyance

[MineYuanlu]

Additional Information

I found another related issue with Function bindings. When binding an array, mutations like push, splice, or direct index assignments do not trigger reactivity. Only reassigning the entire array (e.g., arr = [...arr]) works as expected.

Example:

<script>
	let {arr=$bindable()}=$props();
	function update() {
		arr.push(1); // This won't trigger an update
	}
</script>
data: {JSON.stringify(arr)}
<button onclick={update}>Push</button>

<script>
	let arr_str = '';
</script>

<Module bind:arr={() => arr_str.split(','), (arr) => (arr_str = arr.join(','))} />

Unless the array is reassigned entirely, the binding doesn't respond to changes. This can be confusing, especially when assuming that operations like push would be enough to trigger updates.

[jasonlyu123]

I can't reproduce the error. Can you check if you have svelte.language-server.ls-path config?

[jasonlyu123]

Oh. Never mind, my test workspace has a type definition that overwrites the element type definition.

[MineYuanlu]

I can't reproduce the error. Can you check if you have svelte.language-server.ls-path config?

empty setting

<script lang="ts">
	let w = $state(0);
</script>

<div bind:clientWidth={null, (v) => (w = v)}>content</div>

[bed42]

We're seeing the same exactly bug in our code base too :)