实现compose

js

 //1.实现一个compose函数
    function fn1(x) {
      return x + 1;
    }
    function fn2(x) {
      return x + 2;
    }

    function fn3(x) {
      return x + 3;
    }
    function compose(...fn) {
      return fn.reduce((acc, cur) => {
        return (...args) => acc(cur(...args));
      });
    }
    const fn = compose(fn1, fn2, fn3);

    console.log(fn(1)); // 1+1+2+3 = 7