smartarray/ts/index.ts

export const filter = async <T>(
  arrayArg: T[],
  filterFunction: (itemArg: T) => Promise<boolean>
): Promise<T[]> => {
  const returnArray: T[] = [];
  for (const itemArg of arrayArg) {
    const filterResult = await filterFunction(itemArg);
    if (filterResult) {
      returnArray.push(itemArg);
    }
  }
  return returnArray;
};

export const deduplicate = async <T, K>(
  arrayArg: T[],
  keyCreation: (itemArg: T) => Promise<K>
): Promise<T[]> => {
  const keysSet: Set<K> = new Set();
  const returnArray: T[] = [];

  for (const itemArg of arrayArg) {
    const key = await keyCreation(itemArg);
    if (!keysSet.has(key)) {
      keysSet.add(key);
      returnArray.push(itemArg);
    }
  }

  return returnArray;
};