Function mapRemainingChildren

docs/external/js/react-dom.development.js:13615–13633

(returnFiber, currentFirstChild)

    }

    function mapRemainingChildren(returnFiber, currentFirstChild) {
      // Add the remaining children to a temporary map so that we can find them by
      // keys quickly. Implicit (null) keys get added to this set with their index
      // instead.
      var existingChildren = new Map();
      var existingChild = currentFirstChild;

      while (existingChild !== null) {
        if (existingChild.key !== null) {
          existingChildren.set(existingChild.key, existingChild);
        } else {
          existingChildren.set(existingChild.index, existingChild);
        }

        existingChild = existingChild.sibling;
      }

      return existingChildren;
    }

    function useFiber(fiber, pendingProps) {
      // We currently set sibling to null and index to 0 here because it is easy