el-tree实现单选（父节点可单选）

<template>
  <div>
    <el-tree
      ref="tree"
      :props="props"
      :load="loadNode"
      node-key="name"
      :check-strictly="true" 
      lazy
      show-checkbox
      @check-change="handleCheckChange"
    >
    </el-tree>
  </div>
</template>
<script>
export default {
  data() {
    return {
      props: {
        label: "name",
        children: "zones",
      },
      count: 1,
      selectTreeNum: 0, //选中的树单位
    };
  },
  methods: {
    handleCheckChange(data, checked, indeterminate) {
      this.selectTreeNum++;
      this.$nextTick(() => {
        if (this.selectTreeNum % 2 === 0) {
          // this.selectOrganizationId = 
          if (checked) {
            this.$message.warning("只能选中一个章节");
            this.$refs.tree.setCheckedNodes([]);
            this.$refs.tree.setCheckedNodes([data.name]);
            //交叉点击节点
          } else {
            this.$refs.tree.setCheckedNodes([]);
            //点击已经选中的节点，置空
          }
        } else {
          if (checked) {
            // this.selectOrganizationId = data.organizationId
          }
        }
      });
    },
    handleNodeClick(data) {
      console.log(data);
    },
    loadNode(node, resolve) {
      if (node.level === 0) {
        return resolve([{ name: "region1" }, { name: "region2" }]);
      }
      if (node.level > 3) return resolve([]);

      var hasChild;
      if (node.data.name === "region1") {
        hasChild = true;
      } else if (node.data.name === "region2") {
        hasChild = false;
      } else {
        hasChild = Math.random() > 0.5;
      }

      setTimeout(() => {
        var data;
        if (hasChild) {
          data = [
            {
              name: "zone" + this.count++,
            },
            {
              name: "zone" + this.count++,
            },
          ];
        } else {
          data = [];
        }

        resolve(data);
      }, 500);
    },
  },
};
</script>
<style  scoped lang="less">
</style>