Function cloneUpdateQueue

packages/react-reconciler/src/ReactFiberClassUpdateQueue.js:191–208

(
  current: Fiber,
  workInProgress: Fiber,
)

}

export function cloneUpdateQueue<State>(
  current: Fiber,
  workInProgress: Fiber,
): void {
  // Clone the update queue from current. Unless it's already a clone.
  const queue: UpdateQueue<State> = (workInProgress.updateQueue: any);
  const currentQueue: UpdateQueue<State> = (current.updateQueue: any);
  if (queue === currentQueue) {
    const clone: UpdateQueue<State> = {
      baseState: currentQueue.baseState,
      firstBaseUpdate: currentQueue.firstBaseUpdate,
      lastBaseUpdate: currentQueue.lastBaseUpdate,
      shared: currentQueue.shared,
      callbacks: null,
    };
    workInProgress.updateQueue = clone;
  }
}

export function createUpdate(lane: Lane): Update<mixed> {
  const update: Update<mixed> = {