<el-tree :data="data" ref="tree" node-key="id" :default-expanded-key="idArr"></el-tree>
data() {
return: {
data: [{id:1},{id:2}],
idArr: []
},
created() {
data.forEach(row => {
idArr.push(row.id)
})
}
}
node-key se usa junto con :default-expanded-key