Method tap

src/effected.ts:969–985

* Tap the return value of the effected program. * @param handler The function to tap the return value. * @returns * * @since 0.2.1

(
    handler: (value: R) => void | Generator<F, void, unknown> | Effected<F, void>,
  )

   * @since 0.2.1
   */
  tap<F extends Effect = never>(
    handler: (value: R) => void | Generator<F, void, unknown> | Effected<F, void>,
  ): Effected<E | F, R> {
    return this.andThen((value) => {
      const it = handler(value);
      if (!(it instanceof Effected) && !isGenerator(it)) return value;
      const iterator = it[Symbol.iterator]();
      return {
        _effectedIterator: true,
        next: (...args: [] | [unknown]) => {
          const result = iterator.next(...args);
          if (result.done) return { done: true, value };
          return result;
        },
      };
    }) as never;
  }

  /**
   * Combines the return value of the current effected program with another effected program.