}
  function updateFromMap(
    existingChildren: Map<string | number, Fiber>,
    returnFiber: Fiber,
    newIdx: number,
    newChild: any,
    expirationTime: ExpirationTime,
  ): Fiber | null {
    if (typeof newChild === 'string' || typeof newChild === 'number') {
      
      
      const matchedFiber = existingChildren.get(newIdx) || null;
      return updateTextNode(
        returnFiber,
        matchedFiber,
        '' + newChild,
        expirationTime,
      );
    }
    if (typeof newChild === 'object' && newChild !== null) {
      switch (newChild.$$typeof) {
        case REACT_ELEMENT_TYPE: {
          const matchedFiber =
            existingChildren.get(
              newChild.key === null ? newIdx : newChild.key,
            ) || null;
          if (newChild.type === REACT_FRAGMENT_TYPE) {
            return updateFragment(
              returnFiber,
              matchedFiber,