TreeSelect: Custom Workaround for Programmatic Selection

custom-tree-select.component.ts

export const CUSTOM_TREESELECT_VALUE_ACCESSOR: any = {
  provide: NG_VALUE_ACCESSOR,
  useExisting: forwardRef(() => CustomTreeSelectComponent),
  multi: true
};

interface TreeNodeEvent {
  originalEvent: Event;
  node: TreeNode<any>;
  children: [];
  key: string;
}

@Component({
  selector: 'cx-custom-treeselect',
  templateUrl: './custom-treeselect.component.html',
  styleUrls: ['./custom-treeselect.component.scss'],
  changeDetection: ChangeDetectionStrategy.OnPush,
  providers: [CUSTOM_TREESELECT_VALUE_ACCESSOR],
  encapsulation: ViewEncapsulation.None
})
export class CustomTreeSelectComponent extends TreeSelect implements AfterContentInit {

  iconTypes = ICON_TYPE;
  listId: string = '';
  @Input() ariaLabel: string | undefined;
  @Input() isParentVisible: boolean = true;
  nodes: any;

  override writeValue(value: any): void {
    if (value != null) {
      this.value = this.getNodesFromOptions(value, this.options);
      this.nodes = this.isParentVisible ? this.value : this.removeParentSelection(this.value);
      this.checkParentIfChildrenSelected(this.options);
      this.cd.markForCheck();
    }
  }

  getNodesFromOptions(nodesToFind: any[], options: TreeNodeEvent[]): any[] {
    let nodes: any[] = [];
    nodesToFind.forEach((nodeToFind) => {
      options.forEach((option) => {
        if (option.key === nodeToFind.key) {
          nodes.push(option);
        }
        if (option.children && option.children.length > 0) {
          nodes = nodes.concat(this.getNodesFromOptions([nodeToFind], option.children));
        }
      });
    });
    return nodes;
  }

  checkParentIfChildrenSelected(nodes: TreeNodeEvent[]): void {
    nodes.forEach((node: any) => {
      if (node.children && node.children.length > 0) {
        this.checkParentIfChildrenSelected(node.children);
  
        const allChildrenSelected = node.children.every((child: any) => {
          return this.value.some((selectedNode: any) => selectedNode.key === child.key);
        });
  
        const partialChildrenSelected = node.children.some((child: any) => {
          return this.value.some((selectedNode: any) => selectedNode.key === child.key) || child.partialSelected;
        });
  
        node.partialSelected = partialChildrenSelected && !allChildrenSelected;
  
        if (allChildrenSelected && !this.value.some((selectedNode: any) => selectedNode.key === node.key)) {
          this.value.push(node);
        }
      }
    });
  }
}