svelte/packages/svelte/src/attachments/index.js

import { ATTACHMENT_KEY } from '../constants.js';

/**
 * 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.
 *
 * ```svelte
 * <script>
 * 	import { createAttachmentKey } from 'svelte/attachments';
 *
 * 	const props = {
 * 		class: 'cool',
 * 		onclick: () => alert('clicked'),
 * 		[createAttachmentKey()]: (node) => {
 * 			node.textContent = 'attached!';
 * 		}
 * 	};
 * </script>
 *
 * <button {...props}>click me</button>
 * ```
 * @since 5.29
 */
export function createAttachmentKey() {
	return Symbol(ATTACHMENT_KEY);
}