Alex 552340add7
Feature - Implemented virtual scroll on web (#573)
This PR implemented a virtual scroll on the web, as seen in this article.

[Building the Google Photos Web UI](https://medium.com/google-design/google-photos-45b714dfbed1)
2022-09-04 08:34:39 -05:00

61 lines
1.3 KiB
Svelte

<script context="module" lang="ts">
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: any, target: any = 'body') {
let targetEl;
async function update(newTarget: any) {
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.`
);
}
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>