website/src/theme/prism-include-languages.ts

/**
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
 * @format
 */

import siteConfig from '@generated/docusaurus.config';
import type * as PrismNamespace from 'prismjs';
import type { Optional } from 'utility-types';

export default function prismIncludeLanguages(
    PrismObject: typeof PrismNamespace
): void {
    const {
        themeConfig: { prism },
    } = siteConfig;
    const { additionalLanguages } = prism as { additionalLanguages: string[] };

    // Prism components work on the Prism instance on the window, while prism-
    // react-renderer uses its own Prism instance. We temporarily mount the
    // instance onto window, import components to enhance it, then remove it to
    // avoid polluting global namespace.
    // You can mutate PrismObject: registering plugins, deleting languages... As
    // long as you don't re-assign it

    const PrismBefore = globalThis.Prism;
    globalThis.Prism = PrismObject;

    additionalLanguages.forEach((lang) => {
        if (lang === 'php') {
            // eslint-disable-next-line global-require
            require('prismjs/components/prism-markup-templating.js');
        }
        // eslint-disable-next-line global-require, import/no-dynamic-require
        require(`prismjs/components/prism-${lang}`);
    });

    // Clean up and eventually restore former globalThis.Prism object (if any)
    delete (globalThis as Optional<typeof globalThis, 'Prism'>).Prism;
    if (typeof PrismBefore !== 'undefined') {
        globalThis.Prism = PrismObject;
    }
}