Function mapRemainingChildren

code/new-context-api/public/app.js:8311–8326

(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
    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, expirationTime) {
    // We currently set sibling to null and index to 0 here because it is easy