Function renderFunctionComponent

packages/react-server/src/ReactFizzServer.js:2487–2569

(
  request: Request,
  task: Task,
  keyPath: KeyNode,
  Component: any,
  props: any,
)

let didWarnAboutMaps = false;

function renderFunctionComponent(
  request: Request,
  task: Task,
  keyPath: KeyNode,
  Component: any,
  props: any,
): void {
  let legacyContext;
  if (!disableLegacyContext && !disableLegacyContextForFunctionComponents) {
    legacyContext = getMaskedContext(Component, task.legacyContext);
  }
  if (__DEV__) {
    if (
      Component.prototype &&
      typeof Component.prototype.render === 'function'
    ) {
      const componentName = getComponentNameFromType(Component) || 'Unknown';

      if (!didWarnAboutBadClass[componentName]) {
        console.error(
          "The <%s /> component appears to have a render method, but doesn't extend React.Component. " +
            'This is likely to cause errors. Change %s to extend React.Component instead.',
          componentName,
          componentName,
        );
        didWarnAboutBadClass[componentName] = true;
      }
    }
  }

  const value = renderWithHooks(
    request,
    task,
    keyPath,
    Component,
    props,
    legacyContext,
  );
  if (request.status === ABORTING) {
    // eslint-disable-next-line no-throw-literal
    throw null;
  }

  const hasId = checkDidRenderIdHook();
  const actionStateCount = getActionStateCount();
  const actionStateMatchingIndex = getActionStateMatchingIndex();

  if (__DEV__) {
    if (Component.contextTypes) {
      const componentName = getComponentNameFromType(Component) || 'Unknown';
      if (!didWarnAboutContextTypes[componentName]) {
        didWarnAboutContextTypes[componentName] = true;
        if (disableLegacyContext) {
          console.error(
            '%s uses the legacy contextTypes API which was removed in React 19. ' +
              'Use React.createContext() with React.useContext() instead. ' +
              '(https://react.dev/link/legacy-context)',
            componentName,