Function reconcileChildFibers

code/styling/public/app.js:9622–9696

(returnFiber, currentFirstChild, newChild, expirationTime)

  // itself. They will be added to the side-effect list as we pass through the
  // children and the parent.
  function reconcileChildFibers(returnFiber, currentFirstChild, newChild, expirationTime) {
    // This function is not recursive.
    // If the top level item is an array, we treat it as a set of children,
    // not as a fragment. Nested arrays on the other hand will be treated as
    // fragment nodes. Recursion happens at the normal flow.

    // Handle top level unkeyed fragments as if they were arrays.
    // This leads to an ambiguity between <>{[...]}</> and <>...</>.
    // We treat the ambiguous cases above the same.
    if (typeof newChild === 'object' && newChild !== null && newChild.type === REACT_FRAGMENT_TYPE && newChild.key === null) {
      newChild = newChild.props.children;
    }

    // Handle object types
    var isObject = typeof newChild === 'object' && newChild !== null;

    if (isObject) {
      switch (newChild.$$typeof) {
        case REACT_ELEMENT_TYPE:
          return placeSingleChild(reconcileSingleElement(returnFiber, currentFirstChild, newChild, expirationTime));
        case REACT_PORTAL_TYPE:
          return placeSingleChild(reconcileSinglePortal(returnFiber, currentFirstChild, newChild, expirationTime));
      }
    }

    if (typeof newChild === 'string' || typeof newChild === 'number') {
      return placeSingleChild(reconcileSingleTextNode(returnFiber, currentFirstChild, '' + newChild, expirationTime));
    }

    if (isArray$1(newChild)) {
      return reconcileChildrenArray(returnFiber, currentFirstChild, newChild, expirationTime);
    }

    if (getIteratorFn(newChild)) {
      return reconcileChildrenIterator(returnFiber, currentFirstChild, newChild, expirationTime);
    }

    if (isObject) {
      throwOnInvalidObjectType(returnFiber, newChild);
    }

    {
      if (typeof newChild === 'function') {
        warnOnFunctionType();
      }
    }
    if (typeof newChild === 'undefined') {
      // If the new child is undefined, and the return fiber is a composite
      // component, throw an error. If Fiber return types are disabled,
      // we already threw above.
      switch (returnFiber.tag) {
        case ClassComponent:
          {
            {
              var instance = returnFiber.stateNode;
              if (instance.render._isMockFunction) {
                // We allow auto-mocks to proceed as if they're returning null.
                break;