Function updateOrderedMap

src/OrderedMap.js:119–164

(omap, k, v)

}

function updateOrderedMap(omap, k, v) {
  const map = omap._map;
  const list = omap._list;
  const i = map.get(k);
  const has = i !== undefined;
  let newMap;
  let newList;
  if (v === NOT_SET) {
    // removed
    if (!has) {
      return omap;
    }
    if (list.size >= SIZE && list.size >= map.size * 2) {
      newList = list.filter((entry, idx) => entry !== undefined && i !== idx);
      newMap = newList
        .toKeyedSeq()
        .map((entry) => entry[0])
        .flip()
        .toMap();
      if (omap.__ownerID) {
        newMap.__ownerID = newList.__ownerID = omap.__ownerID;
      }
    } else {
      newMap = map.remove(k);
      newList = i === list.size - 1 ? list.pop() : list.set(i, undefined);
    }
  } else if (has) {
    if (v === list.get(i)[1]) {
      return omap;
    }
    newMap = map;
    newList = list.set(i, [k, v]);
  } else {
    newMap = map.set(k, list.size);
    newList = list.set(list.size, [k, v]);
  }
  if (omap.__ownerID) {
    omap.size = newMap.size;
    omap._map = newMap;
    omap._list = newList;
    omap.__hash = undefined;
    omap.__altered = true;
    return omap;
  }
  return makeOrderedMap(newMap, newList);
}