封装下拉树选择器（亲测多数据一次性加载不卡顿）

花嘴儿是只猫
276 阅读1分钟

用诺依框架时发现他自身封装了下拉树 巨好用一次性加载6k条数据很轻松，所以整理了一下

// TreeSelect.vue 这是封装的组件
<template>
  <div class="el-tree-select">
    <el-select
      style="width: 100%"
      v-model="valueId"
      ref="treeSelect"
      :filterable="true"
      :clearable="true"
      @clear="clearHandle"
      :filter-method="selectFilterData"
      :placeholder="placeholder"
    >
      <el-option :value="valueId" :label="valueTitle">
        <el-tree
          id="tree-option"
          ref="selectTree"
          :accordion="accordion"
          :data="options"
          :props="objMap"
          :node-key="objMap.value"
          :expand-on-click-node="false"
          :default-expanded-keys="defaultExpandedKey"
          :filter-node-method="filterNode"
          @node-click="handleNodeClick"
        ></el-tree>
      </el-option>
    </el-select>
  </div>
</template>

<script setup>

const { proxy } = getCurrentInstance();

const props = defineProps({
  /* 配置项 */
  objMap: {
    type: Object,
    default: () => {
      return {
        value: 'id', // ID字段名
        label: 'label', // 显示名称
        children: 'children' // 子级字段名
      }
    }
  },
  /* 自动收起 */
  accordion: {
    type: Boolean,
    default: () => {
      return false
    }
  },
  /**当前双向数据绑定的值 */
  value: {
    type: [String, Number],
    default: ''
  },
  /**当前的数据 */
  options: {
    type: Array,
    default: () => []
  },
  /**输入框内部的文字 */
  placeholder: {
    type: String,
    default: ''
  }
})

const emit = defineEmits(['update:value']);

const valueId = computed({
  get: () => props.value,
  set: (val) => {
    emit('update:value', val)
  }
});
const valueTitle = ref('');
const defaultExpandedKey = ref([]);

function initHandle() {
  nextTick(() => {
    const selectedValue = valueId.value;
    if(selectedValue !== null && typeof (selectedValue) !== "undefined"){
      const node = proxy.$refs.selectTree.getNode(selectedValue)
      if (node) {
        valueTitle.value = node.data[props.objMap.label]
        proxy.$refs.selectTree.setCurrentKey(selectedValue) // 设置默认选中
        defaultExpandedKey.value = [selectedValue] // 设置默认展开
      }
    }
  })
}
function handleNodeClick(node) {
  valueTitle.value = node[props.objMap.label]
  valueId.value = node[props.objMap.value];
  defaultExpandedKey.value = [];
  proxy.$refs.treeSelect.blur()
  selectFilterData('')
}
function selectFilterData(val) {
  proxy.$refs.selectTree.filter(val)
}
function filterNode(value, data) {
  if (!value) return true
  return data[props.objMap['label']].indexOf(value) !== -1
}
function clearHandle() {
  valueTitle.value = ''
  valueId.value = ''
  defaultExpandedKey.value = [];
  clearSelected()
}
function clearSelected() {
  const allNode = document.querySelectorAll('#tree-option .el-tree-node')
  allNode.forEach((element) => element.classList.remove('is-current'))
}

onMounted(() => {
  initHandle()
})

watch(valueId, () => {
  initHandle();
})
</script>

<style lang='scss' scoped>
@import "@/assets/styles/variables.module.scss";
.el-scrollbar .el-scrollbar__view .el-select-dropdown__item {
  padding: 0;
  background-color: #fff;
  height: auto;
}

.el-select-dropdown__item.selected {
  font-weight: normal;
}

ul li  .el-tree .el-tree-node__content {
  height: auto;
  padding: 0 20px;
  box-sizing: border-box;
}

:deep(.el-tree-node__content:hover),
:deep(.el-tree-node__content:active),
:deep(.is-current > div:first-child),
:deep(.el-tree-node__content:focus) {
  background-color: mix(#fff, $--color-primary, 90%);
  color: $--color-primary;
}
</style>

//下拉树引用的 variables.module.scss文件
// base color
$blue: #324157;
$light-blue: #3A71A8;
$red: #C03639;
$pink: #E65D6E;
$green: #30B08F;
$tiffany: #4AB7BD;
$yellow: #FEC171;
$panGreen: #30B08F;

// 默认菜单主题风格
$base-menu-color: #bfcbd9;
$base-menu-color-active: #f4f4f5;
$base-menu-background: #304156;
$base-logo-title-color: #ffffff;

$base-menu-light-color: rgba(0, 0, 0, 0.7);
$base-menu-light-background: #ffffff;
$base-logo-light-title-color: #001529;

$base-sub-menu-background: #1f2d3d;
$base-sub-menu-hover: #001528;

// 自定义暗色菜单风格
/**
$base-menu-color:hsla(0,0%,100%,.65);
$base-menu-color-active:#fff;
$base-menu-background:#001529;
$base-logo-title-color: #ffffff;

$base-menu-light-color:rgba(0,0,0,.70);
$base-menu-light-background:#ffffff;
$base-logo-light-title-color: #001529;

$base-sub-menu-background:#000c17;
$base-sub-menu-hover:#001528;
*/

$--color-primary: #409EFF;
$--color-success: #67C23A;
$--color-warning: #E6A23C;
$--color-danger: #F56C6C;
$--color-info: #909399;

$base-sidebar-width: 200px;

// the :export directive is the magic sauce for webpack
// https://www.bluematador.com/blog/how-to-share-variables-between-js-and-sass
:export {
  menuColor: $base-menu-color;
  menuLightColor: $base-menu-light-color;
  menuColorActive: $base-menu-color-active;
  menuBackground: $base-menu-background;
  menuLightBackground: $base-menu-light-background;
  subMenuBackground: $base-sub-menu-background;
  subMenuHover: $base-sub-menu-hover;
  sideBarWidth: $base-sidebar-width;
  logoTitleColor: $base-logo-title-color;
  logoLightTitleColor: $base-logo-light-title-color;
  primaryColor: $--color-primary;
  successColor: $--color-success;
  dangerColor: $--color-danger;
  infoColor: $--color-info;
  warningColor: $--color-warning;
}

我们如何使用呢？

// 页面使用
              <tree-select
                v-model:value="form.parentId"
                :options="deptOptions"
                :objMap="{
                  value: 'deptId',
                  label: 'deptName',
                  children: 'children',
                }"
                placeholder="选择上级部门"
              />

//js部分
//发请求拿数据
const getDeptList = async () => {
  await listDept().then((response) => {
    deptOptions.value = proxy.handleTree(response.data, "deptId");
  });
};

// 请求回来的数据结构 image.png

// handleTree算法
/**
 * 构造树型结构数据
 * @param {*} data 数据源
 * @param {*} id id字段 默认 'id'
 * @param {*} parentId 父节点字段 默认 'parentId'
 * @param {*} children 孩子节点字段 默认 'children'
 */
export function handleTree(data, id, parentId, children) {
  let config = {
    id: id || 'id',
    parentId: parentId || 'parentId',
    childrenList: children || 'children'
  };

  var childrenListMap = {};
  var nodeIds = {};
  var tree = [];

  for (let d of data) {
    let parentId = d[config.parentId];
    if (childrenListMap[parentId] == null) {
      childrenListMap[parentId] = [];
    }
    nodeIds[d[config.id]] = d;
    childrenListMap[parentId].push(d);
  }

  for (let d of data) {
    let parentId = d[config.parentId];
    if (nodeIds[parentId] == null) {
      tree.push(d);
    }
  }

  for (let t of tree) {
    adaptToChildrenList(t);
  }

  function adaptToChildrenList(o) {
    if (childrenListMap[o[config.id]] !== null) {
      o[config.childrenList] = childrenListMap[o[config.id]];
    }
    if (o[config.childrenList]) {
      for (let c of o[config.childrenList]) {
        adaptToChildrenList(c);
      }
    }
  }
  return tree;
}
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