How to expand all parent node of particular child node using nested tree control of mat tree in angular 8?

Question

getBookOutlineBar method will take a list of nodes and the selected node which needs to be selected when sidebar of outline opens. I have implemented expand method to expand all parent node but it is only expanding one particular node, not all parent nodes. If page "Heading" is opened and I click on outline sidebar than all parent nodes should be expanded and heading should be selected. I have used nested tree control of mat tree in angular 8. (this example is used in my code: https://stackblitz.com/angular/dklgxbrynad?file=src%2Fapp%2Ftree-nested-overview-example.ts). Please suggest any help.

getBookOutlineBar() {
        let customURL = '';
        this.bookService.GetBookOutlineBar(this.bookId, location.hash).subscribe(data => {
          this.dataSource.data = data.list;
          if (data.selectedNode != null) {
            this.selectedNode = data.selectedNode;
            this.treeControl.collapseAll();
            this.expand(this.dataSource.data, this.selectedNode.UniqueId);
          }    
        })
      }
    expand(data: BookOutlineBar[], uniqueId: string): any {
        data.forEach(node => {
          if (node.Children && node.Children.find(c => c.UniqueId === uniqueId)) {
            this.treeControl.expand(node);
            this.expand(this.treeControl.dataNodes, node.UniqueId);
          }
          else if (node.Children && node.Children.find(c => c.Children)) {
            this.expand(node.Children, uniqueId);
          }
        });
      }

Krupit Patel Krupit Patel · Accepted Answer · 2020-06-19T05:32:56

Your code

 if (node.Children && node.Children.find(c => c.UniqueId === uniqueId)) {
            this.treeControl.expand(node);
            this.expand(this.treeControl.dataNodes, node.UniqueId);
          }

Replace with

 if (node.Children && node.Children.find(c => c.UniqueId === uniqueId)) {
            this.treeControl.expand(node);
            this.expand(this.dataSource.data, node.UniqueId);
          }

How to expand all parent node of particular child node using nested tree control of mat tree in angular 8?

1 Answers