Vue2 + element ui el-select 远程搜索分页懒加载功能实现_el-select 分页加载

新建指令 ：

        1、 在 src 目录下 新建文件夹 directive / loadmore

        2、在 loadmore 文价夹下新建 elSelectLoadmore.js 和 index.js 文件：        

   elSelectLoadmore.js

export default {
    inserted(el, binding, vnode) {
      const SELECTWRAP_DOM = el.querySelector('.el-select-dropdown .el-select-dropdown__wrap');
      SELECTWRAP_DOM.addEventListener('scroll', function() {
        const condition = Math.floor(this.scrollHeight - this.scrollTop) <= this.clientHeight;
        if (condition) {
          binding.value();
        }
      });
    }
  };

index.js

import elSelectLoadmore from './elSelectLoadmore';
const install = function(Vue) {
  Vue.directive('el-select-loadmore', elSelectLoadmore);
};
if (window.Vue) {
    window['el-select-loadmore'] = elSelectLoadmore
    Vue.use(install); // eslint-disable-line
  }
export default install;

3、在main 文件中注册该指令

import elSelectLoadmore from './directive/loadmore'
 
 
Vue.use(elSelectLoadmore)

4、 基于 el-select 封装 懒加载 远程搜索框

remoteSelect.vue

<template>
    <el-select
        ref="remoteSelect"
        :disabled="disabled"
        style="width:100%"
        v-model="remoteCode"
        filterable
        remote
        clearable
        reserve-keyword
        placeholder="请输入软件id / 软件名称"
        :remote-method="remoteMethod"
        v-el-select-loadmore="loadmore"
        :loading="loading"
        @input="input"
        :multiple="multiple"
    >
        <el-option
            v-for="item in options"
            :key="item.id"
            :label="item.id + ' ' +item.name"
            :value="item.id"
        >
        </el-option>
        <div class="uploadTip"  
            v-if="loadMoreLoading &&  !loadNoMore"
        >数据加载中......</div>
        <div 
            class="uploadTip" 
            v-if="loadNoMore" 
        >暂无更多数据</div>
    </el-select>
</template>
<script>
import { getSoftwareForRef } from "@/api/softwar/manage";
export default {
    name:'remote-select',
    props:{
        value:{
            type:[Number, String, Array],
            default:undefined
        },
        disabled:{
            type: Boolean,
            default:false
        },
        multiple:{
            type:Boolean,
            default:false
        },
        status:{
            type:Number,
            default:undefined
        }
    },
    data(){
        return {
            remoteQuery:{
                pageNum:1,
                pageSize:10,
                status:this.status //接口状态参数
            },
            options:[],
            loading:false,            // 组件搜索加载中参数
            loadMoreLoading:false,    // 翻页加载中参数
            remoteCode:undefined,     // select value
            loadNoMore:false          // 没有更多的状态
        }
    },
    mounted(){
    },
    watch:{
        value: {
            handler(data) {
                this.remoteCode = data
            },
            immediate: true
        },
    },
    methods: {
        input(val){
            this.$emit('input',val)
            const index = this.options.findIndex(i => i.id === val)
            this.$emit('inputAll', index === -1 ? val : this.options[index])
        },
        remoteMethod(query, review) {
            this.loading = true
            this.loadNoMore = false
            this.remoteQuery.pageNum = 1
            if(typeof query === 'object'){
                this.remoteQuery.swIds = query
            }else{
                this.remoteQuery.param = query
                delete this.remoteQuery.swIds
            }
            this.remoteQuery.status = this.status
            getSoftwareForRef(this.remoteQuery).then(res => {
                this.options = res.data
                this.loading = false;
                if(typeof review === 'boolean' && review){
                    let index = this.options.findIndex(i => i.id === this.value)
                    if(index !== -1){
                        this.remoteCode = this.value + ' ' + this.options[index].name
                    }else{
                        this.remoteCode = this.value
                    }
                }
            })
        },
        loadmore(){
            if(this.loadMoreLoading){
                return
            }
            var remoteQuery = {...this.remoteQuery};
            remoteQuery.pageNum++;
            this.loadMoreLoading = true
            getSoftwareForRef(remoteQuery).then(res => {
                if(res.code === 0 && typeof res.data === 'object' && res.data.length){
                    this.options = this.options.concat(res.data)
                    this.remoteQuery.pageNum++ 
                }
                if(res.code === 0 && typeof res.data === 'object' && res.data.length === 0){
                    this.loadNoMore = true;
                }
                this.$nextTick(() => {
                    setTimeout(() => {
                        this.loadMoreLoading = false
                    }, 500)
                })
            }).catch(err => {
                this.$nextTick(() => {
                    setTimeout(() => {
                        this.loadMoreLoading = false
                    }, 500)
                })
            })
 
        },
        setValue(){
            typeof this.value === 'object' ? this.remoteMethod(this.value) : this.remoteMethod(this.value, true)
        },
        clearOptions(){
            this.options = []
        }
    },
    
}
    
</script>
<style scoped>
.uploadTip{
    width: 100%;
    text-align: center;
}
</style>

组件提示 tips：

        由于组件搜索下拉框分页通过 scroll 事件实现的 

        所以远程加载提示涉及到元素隐藏和显示会一直触发 scroll 到底事件；

        需要常驻！！！！

        错误例子： 在 options 底部加载中显示 <div>加载中。。。</div> 接口请求结束在隐藏