ElementUI el-tree 屬性空間實現單選

<template>
    <div class="tree">     
    <el-tree :data="data2" show-checkbox node-key="id" default-expand-all   
    @check-change="handleClick" ref="treeForm" @node-click="nodeClick">
    </el-tree>
    </div>
</template>

<script>
    export default {
        data () {
            return {
                 data2: [{
                    id: 1,
                    label: '一級 1',
                    children: [{
                        id: 4,
                        label: '二級 1-1',
                        children: [{
                            id: 9,
                            label: '三級 1-1-1'
                        }, {
                            id: 10,
                            label: '三級 1-1-2'
                        }]
                    }]
                }, {
                    id: 2,
                    label: '一級 2',
                    children: [{
                        id: 5,
                        label: '二級 2-1',
                    }, {
                        id: 6,
                        label: '二級 2-2'
                    }]
                }, {
                    id: 3,
                    label: '一級 3',
                    children: [{
                        id: 7,
                        label: '二級 3-1'
                    }, {
                        id: 8,
                        label: '二級 3-2'
                    }]
                }],
                checkedId:null
            }
        },
        methods: {
            handleClick(data, checked, node){
                 if(checked == true){
                     this.checkedId = data.id;
                     this.$refs.treeForm.setCheckedNodes([data]);
                 }
            },
            nodeClick(data,checked,node){
                this.checkedId = data.id
                this.$refs.treeForm.setCheckedNodes([data]);
                
            }
        }
    }
</script>

<style scoped>

</style>