<docs>
---
order: 5
title:
  zh-CN: 异步加载
  en-US: Asynchronous loading
---

## zh-CN

异步加载树节点。

## en-US

Asynchronous loading tree node.

</docs>
<template>
  <a-tree-select
    v-model:value="value"
    tree-data-simple-mode
    style="width: 100%"
    :dropdown-style="{ maxHeight: '400px', overflow: 'auto' }"
    :tree-data="treeData"
    placeholder="Please select"
    :load-data="onLoadData"
  />
</template>

<script lang="ts" setup>
import type { TreeSelectProps } from 'ant-design-vue';
import { ref, watch } from 'vue';
const value = ref<string>();
const treeData = ref<TreeSelectProps['treeData']>([
  { id: 1, pId: 0, value: '1', title: 'Expand to load' },
  { id: 2, pId: 0, value: '2', title: 'Expand to load' },
  { id: 3, pId: 0, value: '3', title: 'Tree Node', isLeaf: true },
]);

watch(value, () => {
  console.log(value.value);
});

const genTreeNode = (parentId: number, isLeaf = false): TreeSelectProps['treeData'][number] => {
  const random = Math.random().toString(36).substring(2, 6);
  return {
    id: random,
    pId: parentId,
    value: random,
    title: isLeaf ? 'Tree Node' : 'Expand to load',
    isLeaf,
  };
};
const onLoadData = (treeNode: TreeSelectProps['treeData'][number]) => {
  return new Promise(resolve => {
    const { id } = treeNode.dataRef;
    setTimeout(() => {
      treeData.value = treeData.value.concat([
        genTreeNode(id, false),
        genTreeNode(id, true),
        genTreeNode(id, true),
      ]);
      console.log(treeData.value);
      resolve(true);
    }, 300);
  });
};
</script>
