static-html.ts — astro Source File

Source Code

import { h } from 'preact';

type Props = {
	value: string;
	name?: string;
	hydrate?: boolean;
};

/**
 * Astro passes `children` as a string of HTML, so we need
 * a wrapper `div` to render that content as VNodes.
 *
 * As a bonus, we can signal to Preact that this subtree is
 * entirely static and will never change via `shouldComponentUpdate`.
 */
const StaticHtml = ({ value, name, hydrate = true }: Props) => {
	if (!value) return null;
	const tagName = hydrate ? 'astro-slot' : 'astro-static-slot';
	return h(tagName, { name, dangerouslySetInnerHTML: { __html: value } });
};

/**
 * This tells Preact to opt-out of re-rendering this subtree,
 * In addition to being a performance optimization,
 * this also allows other frameworks to attach to `children`.
 *
 * See https://preactjs.com/guide/v8/external-dom-mutations
 */
StaticHtml.shouldComponentUpdate = () => false;

export default StaticHtml;