`ontoggle` in `details` is fired before updating `bind:open`

[keithyipkw]

Describe the bug

ontoggle should be fired after updating bind:open, not before. Quote from https://svelte.dev/docs/svelte/basic-markup#Events

Timing-wise, event attributes always fire after events from bindings (e.g. oninput always fires after an update to bind:value).

Reproduction

The following code can reproduce the problem in the Svelte playground

<script>
	let bindingState = false;
	
	let ontoggleState = false;
	
	const ontoggle = () => {
		ontoggleState = bindingState;
	}
</script>

<details bind:open={bindingState} ontoggle={ontoggle} >
<div>Opened</div>
</details>

<p>
	Reactive value: {bindingState}
</p>

<p>
	Reactive value inside ontoggle: {ontoggleState}
</p>

Logs

System Info

svelte: 5.45.5

Severity

annoyance