const selectDom = document.querySelector('.single-select-loadmore .el-select-dropdown__wrap')

// src/directive/elSelectLoadMore.js
export default {
  mounted(el, binding, vnode) {
    const selectDom = vnode.children[0].component.refs.popperRef.contentRef.querySelector('.el-select-dropdown .el-select-dropdown__wrap');
    function loadMores() {
      // 判斷是否到底
      const isBottom = this.scrollHeight - this.scrollTop <= this.clientHeight;
      if (isBottom) {
        // 執(zhí)行事件回調(diào)
        binding.value && binding.value();
      }
    }
    // 將獲取到的dom和函數(shù)掛載到el-select上，以便實例銷毀時進行事件移除處理
    el._selectDom = selectDom;
    el._selectLoadMore = loadMores;
    // 監(jiān)聽滾動事件
    selectDom?.addEventListener('scroll', loadMores.bind(selectDom));
  },
  // 實例銷毀
  beforeUnmount(el) {
    if (el._selectLoadMore) {
      el._selectDom.removeEventListener('scroll', el._selectLoadMore);
      delete el._selectDom;
      delete el._selectLoadMore;
    }
  }
}

// src/directive/index.js
import elSelectLoadMore from './common/elSelectLoadMore'
export default function directive(app){
  app.directive('selectLoadmore', elSelectLoadMore)
}

// src/main.js
import App from './App'
import directive from './directive'
const app = createApp(App)
directive(app)