Function preloadModule

packages/react-dom-bindings/src/client/ReactFiberConfigDOM.js:4773–4828

(href: string, options?: ?PreloadModuleImplOptions)

}

function preloadModule(href: string, options?: ?PreloadModuleImplOptions) {
  previousDispatcher.m(/* preloadModule */ href, options);
  const ownerDocument = getGlobalDocument();
  if (ownerDocument && href) {
    const as =
      options && typeof options.as === 'string' ? options.as : 'script';
    const preloadSelector = `link[rel="modulepreload"][as="${escapeSelectorAttributeValueInsideDoubleQuotes(
      as,
    )}"][href="${escapeSelectorAttributeValueInsideDoubleQuotes(href)}"]`;
    // Some preloads are keyed under their selector. This happens when the preload is for
    // an arbitrary type. Other preloads are keyed under the resource key they represent a preload for.
    // Here we figure out which key to use to determine if we have a preload already.
    let key = preloadSelector;
    switch (as) {
      case 'audioworklet':
      case 'paintworklet':
      case 'serviceworker':
      case 'sharedworker':
      case 'worker':
      case 'script': {
        key = getScriptKey(href);
        break;
      }
    }

    if (!preloadPropsMap.has(key)) {
      const props: PreloadModuleProps = Object.assign(
        ({
          rel: 'modulepreload',
          href,
        }: PreloadModuleProps),
        options,
      );
      preloadPropsMap.set(key, props);

      if (null === ownerDocument.querySelector(preloadSelector)) {
        switch (as) {
          case 'audioworklet':
          case 'paintworklet':
          case 'serviceworker':
          case 'sharedworker':
          case 'worker':
          case 'script': {
            if (ownerDocument.querySelector(getScriptSelectorFromKey(key))) {
              return;
            }
          }
        }
        const instance = ownerDocument.createElement('link');
        setInitialProperties(instance, 'link', props);
        markNodeAsHoistable(instance);
        (ownerDocument.head: any).appendChild(instance);
      }
    }
  }
}

function preinitStyle(