prefetchDNS() — react Function Reference

Source Code

packages/react-dom/src/shared/ReactDOMFloat.js lines 24–56

export function prefetchDNS(href: string) {
  if (__DEV__) {
    if (typeof href !== 'string' || !href) {
      console.error(
        'ReactDOM.prefetchDNS(): Expected the `href` argument (first) to be a non-empty string but encountered %s instead.',
        getValueDescriptorExpectingObjectForWarning(href),
      );
    } else if (arguments.length > 1) {
      const options = arguments[1];
      if (
        typeof options === 'object' &&
        options.hasOwnProperty('crossOrigin')
      ) {
        console.error(
          'ReactDOM.prefetchDNS(): Expected only one argument, `href`, but encountered %s as a second argument instead. This argument is reserved for future options and is currently disallowed. It looks like the you are attempting to set a crossOrigin property for this DNS lookup hint. Browsers do not perform DNS queries using CORS and setting this attribute on the resource hint has no effect. Try calling ReactDOM.prefetchDNS() with just a single string argument, `href`.',
          getValueDescriptorExpectingEnumForWarning(options),
        );
      } else {
        console.error(
          'ReactDOM.prefetchDNS(): Expected only one argument, `href`, but encountered %s as a second argument instead. This argument is reserved for future options and is currently disallowed. Try calling ReactDOM.prefetchDNS() with just a single string argument, `href`.',
          getValueDescriptorExpectingEnumForWarning(options),
        );
      }
    }
  }
  if (typeof href === 'string') {
    ReactDOMSharedInternals.d /* ReactDOMCurrentDispatcher */
      .D(/* prefetchDNS */ href);
  }
  // We don't error because preconnect 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.
}