비동기 파이프라인 패턴

• 동기/비동기 함수 체이닝 실행 유틸

  •   const pipe = (...fns) => (arg) => 
        fns.reduce(
          (result, fn) => (fn instanceof Function ? result.then(fn) : result),
          Promise.resolve(arg)
        );

  •   const pipe = (...fns) => (arg) =>
        fns.reduce((result, fn) => result.then(fn), Promise.resolve(arg));
      
      const add = (x) => x + 1;
      const double = async (x) => x * 2;
      const subtract = (x) => x - 3;
      
      const run = pipe(add, double, subtract);
      run(5).then(console.log); // 5 + 1 = 6 → await double(6) = 12 → 12 - 3 = 9