createRemoveScheme.js

/*
 *  see: [https://stackoverflow.com/questions/66303388/how-to-most-efficiently-splice-an-array-while-looping-through-a-list-of-indices/66304184#66304184]
 *
 *  StackOverflow :: How to most efficiently splice an array
 *                   while looping through a list of indices
 *                   of to be removed array items?
 */

function createRemoveScheme(indexList, targetList) {
  return Array
    .from(indexList)
    .sort((a, b) => a - b)
    .reduce((schema, currentPos, idx, referenceList) => {

      const { rangeList } = schema;
      let range;

      const recentPos = referenceList[idx - 1] ?? null;
      const nextPos = referenceList[idx + 1] ?? null;

      const isOpenNewRange = (
        (recentPos === null) ||
        (currentPos - recentPos !== 1)
      );
      const isTerminateRange = (recentPos !== null) && (
        (nextPos === null) ||
        (nextPos - currentPos !== 1)
      );

    if (isOpenNewRange) {

      range = [ currentPos ];
      rangeList.push(range);
    }
    if (isTerminateRange) {

      range = rangeList[rangeList.length - 1];
      range.push(currentPos);
    }
    return schema;

  }, { target: targetList, rangeList: [] });
}