If a node hasn't any children, its state can't be set to 'closed'. It will be a leaf node.

But i using lazy load,so don't know if this node have childs or not

i using Tree component with lazy-load, everything looks good, but in case a node does not have any children and result is empty, the loading icon does not disappear, So I did something wrong or this is an issue of component ?

Code:

onNodeExpand(event){
        let node = event;
        if (!node.children) {
            this.dataService.getNodes(node).subscribe((data) => node.children = data);
            // data = [] when this node doesn't have any child
        }
 }