vendors/tempy.js/splitWhen
    function splitWhen(items, predicate) {
      const result = [[]];
      let groupIndex = 0;
      for (const item of items) {
        if (predicate(item)) {
          groupIndex++;
          result[groupIndex] = [];
        } else {
          result[groupIndex].push(item);
        }
      }
      return result;
    }