splitArray.tsx

export function splitArray<T>(
  array: ReadonlyArray<T>,
  predicate: (value: T) => boolean,
): _.Dictionary<ReadonlyArray<T>> {
  return array.reduce(
    (accu, value) => {
      if (predicate(value)) {
        return {
          ...accu,
          truthyPart: [...accu.truthyPart, value],
        };
      }

      return {
        ...accu,
        falsyPart: [...accu.falsyPart, value],
      };
    },
    // default value
    {
      truthyPart: [],
      falsyPart: [],
    },
  );
}