koa2-compose源码是否可以做如下修改？

Question

https://github.com/koajs/comp...
//源码链接

//koa 源码callback（）中
 const fn = compose(this.middleware);

 fn(ctx).then(handleResponse).catch(onerror); //fn是compose后的结果，只传入了一个ctx，意味着下面返回函数的next参数为undefined

//compose
function compose (middleware) {
....
return function (context, next) { //使用时next参数并没有传入，该参数是否有必要？
    // last called middleware #
    let index = -1
    return dispatch(0)
    function dispatch (i) {
      if (i <= index) return Promise.reject(new Error('next() called multiple times'))
      index = i
      let fn = middleware[i]    
      if (i === middleware.length) fn = next//是否可以去掉这行？因为js数组不考虑越界，当越界时是undefined  ，next未被传入所以也是undefined
      if (!fn) return Promise.resolve()
     
      try {
        return Promise.resolve(fn(context, function next () {
          return dispatch(i + 1)
        }))
      } catch (err) {
        return Promise.reject(err)
      }
    }
  }
}
｝