Function addCheckpointImpl

docs/pseudo.esm.sh/tinybase@9.0.0/index.js:507–517

(label = EMPTY_STRING)

    let cellListenerId;
    let valueListenerId;
    const addCheckpointImpl = (label = EMPTY_STRING) => {
      if (isUndefined(currentId)) {
        currentId = EMPTY_STRING + nextCheckpointId++;
        mapSet(deltas, currentId, [cellsDelta, valuesDelta]);
        setCheckpoint(currentId, label);
        cellsDelta = mapNew();
        valuesDelta = mapNew();
        checkpointsChanged = 1;
      }
      return currentId;
    };
    const goBackwardImpl = () => {
      if (!arrayIsEmpty(backwardIds)) {
        arrayUnshift(forwardIds, addCheckpointImpl());