<mat-tree [dataSource]="dataSource" [treeControl]="treeControl">
  <mat-tree-node *matTreeNodeDef="let node" matTreeNodePadding>
    <button mat-icon-button class="hidden"></button>
    {{node.name}}
  </mat-tree-node>
  <mat-tree-node *matTreeNodeDef="let node;when: hasChild" matTreeNodePadding>
    <button mat-icon-button matTreeNodeToggle class="icon-button"
            [attr.aria-label]="'toggle ' + node.name" color="black">
      <set-icon shape="chevron_right"
                [attr.dir]="treeControl.isExpanded(node) ? 'right' : 'up'">
      </set-icon>
    </button>
    {{node.name}}
  </mat-tree-node>
</mat-tree>