svelte/attachments

import { import createAttachmentKeycreateAttachmentKey } from 'svelte/attachments';

createAttachmentKey

Available since 5.29

Creates an object key that will be recognised as an attachment when the object is spread onto an element, as a programmatic alternative to using {@attach ...}. This can be useful for library authors, though is generally not needed when building an app.

<script>
	import { createAttachmentKey } from 'svelte/attachments';

	const props = {
		class: 'cool',
		onclick: () => alert('clicked'),
		[createAttachmentKey()]: (node) => {
			node.textContent = 'attached!';
		}
	};
</script>

<button {...props}>click me</button>

function createAttachmentKey(): symbol;

Attachment

An attachment is a function that runs when an element is mounted to the DOM, and optionally returns a function that is called when the element is later removed.

It can be attached to an element with an {@attach ...} tag, or by spreading an object containing a property created with createAttachmentKey.

interface Attachment<T extends EventTarget = Element> {…}

(element: T): void | (() => void);