ant-design-vue/antdv-demo/docs/tree/demo/switcher-icon.md

#### 自定义展开/折叠图标 自定义展开/折叠图标。 #### Customize collapse/expand icon customize collapse/expand icon of tree node

<template>
  <a-tree show-line :default-expanded-keys="['0-0-0']" @select="onSelect">
    <a-icon slot="switcherIcon" type="down" />
    <a-tree-node key="0-0" title="parent 1">
      <a-tree-node key="0-0-0" title="parent 1-0">
        <a-tree-node key="0-0-0-0" title="leaf" />
        <a-tree-node key="0-0-0-1" title="leaf" />
        <a-tree-node key="0-0-0-2" title="leaf" />
      </a-tree-node>
      <a-tree-node key="0-0-1" title="parent 1-1">
        <a-tree-node key="0-0-1-0" title="leaf" />
      </a-tree-node>
      <a-tree-node key="0-0-2" title="parent 1-2">
        <a-tree-node key="0-0-2-0" title="leaf" />
        <a-tree-node key="0-0-2-1" title="leaf" />
      </a-tree-node>
    </a-tree-node>
  </a-tree>
</template>
<script>
export default {
  methods: {
    onSelect(selectedKeys, info) {
      console.log('selected', selectedKeys, info);
    },
  },
};
</script>