Function addCheckpointImpl

src/checkpoints/index.ts:133–143

(label = EMPTY_STRING)

    let valueListenerId: string;

    const addCheckpointImpl = (label = EMPTY_STRING): Id => {
      if (isUndefined(currentId)) {
        currentId = EMPTY_STRING + nextCheckpointId++;
        mapSet(deltas, currentId, [cellsDelta, valuesDelta]);
        setCheckpoint(currentId, label);
        cellsDelta = mapNew();
        valuesDelta = mapNew();
        checkpointsChanged = 1;
      }
      return currentId as Id;
    };

    const goBackwardImpl = () => {
      if (!arrayIsEmpty(backwardIds)) {