preinit() — react Function Reference

Source Code

packages/react-dom/src/shared/ReactDOMFloat.js lines 205–260

export function preinit(href: string, options: PreinitOptions) {
  if (__DEV__) {
    if (typeof href !== 'string' || !href) {
      console.error(
        'ReactDOM.preinit(): Expected the `href` argument (first) to be a non-empty string but encountered %s instead.',
        getValueDescriptorExpectingObjectForWarning(href),
      );
    } else if (options == null || typeof options !== 'object') {
      console.error(
        'ReactDOM.preinit(): Expected the `options` argument (second) to be an object with an `as` property describing the type of resource to be preinitialized but encountered %s instead.',
        getValueDescriptorExpectingEnumForWarning(options),
      );
    } else if (options.as !== 'style' && options.as !== 'script') {
      console.error(
        'ReactDOM.preinit(): Expected the `as` property in the `options` argument (second) to contain a valid value describing the type of resource to be preinitialized but encountered %s instead. Valid values for `as` are "style" and "script".',
        getValueDescriptorExpectingEnumForWarning(options.as),
      );
    }
  }
  if (typeof href === 'string' && options && typeof options.as === 'string') {
    const as = options.as;
    const crossOrigin = getCrossOriginStringAs(as, options.crossOrigin);
    const integrity =
      typeof options.integrity === 'string' ? options.integrity : undefined;
    const fetchPriority =
      typeof options.fetchPriority === 'string'
        ? options.fetchPriority
        : undefined;
    if (as === 'style') {
      ReactDOMSharedInternals.d /* ReactDOMCurrentDispatcher */
        .S(
          /* preinitStyle */
          href,
          typeof options.precedence === 'string'
            ? options.precedence
            : undefined,
          {
            crossOrigin,
            integrity,
            fetchPriority,
          },
        );
    } else if (as === 'script') {
      ReactDOMSharedInternals.d /* ReactDOMCurrentDispatcher */
        .X(/* preinitScript */ href, {
          crossOrigin,
          integrity,
          fetchPriority,
          nonce: typeof options.nonce === 'string' ? options.nonce : undefined,
        });
    }
  }
  // We don't error because preinit needs to be resilient to being called in a variety of scopes
  // and the runtime may not be capable of responding. The function is optimistic and not critical
  // so we favor silent bailout over warning or erroring.
}