windmill/frontend/src/lib/components/Portal.svelte

<script context="module">
	import { tick } from 'svelte'

	/**
	 * Usage: <div use:portal={'css selector'}> or <div use:portal={document.body}>
	 *
	 * @param {HTMLElement} el
	 * @param {HTMLElement|string} target DOM Element or CSS Selector
	 */
	export function portal(el, target = 'body') {
		let targetEl
		async function update(newTarget) {
			target = newTarget
			if (typeof target === 'string') {
				targetEl = document.querySelector(target)
				if (targetEl === null) {
					await tick()
					targetEl = document.querySelector(target)
				}
				if (targetEl === null) {
					throw new Error(`No element found matching css selector: "${target}"`)
				}
			} else if (target instanceof HTMLElement) {
				targetEl = target
			} else {
				throw new TypeError(
					`Unknown portal target type: ${
						target === null ? 'null' : typeof target
					}. Allowed types: string (CSS selector) or HTMLElement.`
				)
			}
			if (!el.classList.contains('windmill-app')) {
				el.classList.add('windmill-app')
			}
			targetEl.appendChild(el)
			el.hidden = false
		}

		function destroy() {
			if (el.parentNode) {
				el.parentNode.removeChild(el)
			}
		}

		update(target)
		return {
			update,
			destroy
		}
	}
</script>

<script>
	/**
	 * DOM Element or CSS Selector
	 * @type { HTMLElement|string}
	 */
	export let target = 'body'
</script>

<div use:portal={target} hidden>
	<slot />
</div>