antvG6 点击节点获取后台数据

// 我这边的需求是点击节点只获取该节点的下一级

graph.on('node:click',async(ev)=>{

    if(ev,item._cfg.model.children){return}

    const subData = res; //res是后台返回的数据
    
    const el = graph.findById(ev.item._cfg.id)

    el._cfg.model.children = subData;

    graph.refreshItem(el)

     graph.render()

})