Function mapEnsure

src/common/map.ts:60–72

(
  map: Map<Key, Value>,
  key: Key,
  getDefaultValue: () => Value,
  hadExistingValue?: (value: Value) => void,
)

  });

export const mapEnsure = <Key, Value>(
  map: Map<Key, Value>,
  key: Key,
  getDefaultValue: () => Value,
  hadExistingValue?: (value: Value) => void,
): Value => {
  if (!collHas(map, key)) {
    mapSet(map, key, getDefaultValue());
  } else {
    hadExistingValue?.(mapGet(map, key) as Value);
  }
  return mapGet(map, key) as Value;
};

export const mapMatch = <MapValue, ObjValue>(
  map: IdMap<MapValue>,