Function reconcileSingleElement

docs/external/js/react-dom.development.js:14298–14374

(returnFiber, currentFirstChild, element, expirationTime)

    }

    function reconcileSingleElement(returnFiber, currentFirstChild, element, expirationTime) {
      var key = element.key;
      var child = currentFirstChild;

      while (child !== null) {
        // TODO: If key === null and child.key === null, then this only applies to
        // the first item in the list.
        if (child.key === key) {
          switch (child.tag) {
            case Fragment:
              {
                if (element.type === REACT_FRAGMENT_TYPE) {
                  deleteRemainingChildren(returnFiber, child.sibling);
                  var existing = useFiber(child, element.props.children);
                  existing.return = returnFiber;

                  {
                    existing._debugSource = element._source;
                    existing._debugOwner = element._owner;
                  }

                  return existing;
                }

                break;
              }

            case Block:

            // We intentionally fallthrough here if enableBlocksAPI is not on.
            // eslint-disable-next-lined no-fallthrough

            default:
              {
                if (child.elementType === element.type || ( // Keep this check inline so it only runs on the false path:
                 isCompatibleFamilyForHotReloading(child, element) )) {
                  deleteRemainingChildren(returnFiber, child.sibling);

                  var _existing3 = useFiber(child, element.props);

                  _existing3.ref = coerceRef(returnFiber, child, element);
                  _existing3.return = returnFiber;

                  {
                    _existing3._debugSource = element._source;
                    _existing3._debugOwner = element._owner;
                  }

                  return _existing3;
                }

                break;
              }
          } // Didn't match.


          deleteRemainingChildren(returnFiber, child);
          break;