题解 | #数组排序#

   function up() {
        return cups.sort((a, b) => a.sales - b.sales)
      }
      function down() {
        return cups.sort((a, b) => {
          return b.sales - a.sales
        })
      }
      upbtn.onclick = function () {
        let info = up()
        renderHtml(info)
      }
      downbtn.onclick = function () {
        let info = down()
        renderHtml(info)
      }

      function renderHtml(arr) {
        ul.innerHTML = ''
        let frame = document.createDocumentFragment()
        arr.forEach((item) => {
          let li = document.createElement('li')
          li.innerText = item.name
          frame.appendChild(li)
        })
        ul.appendChild(frame)
      }
      renderHtml(cups)