constructor()

in docs-content/examples-source/material/tree/tree-checklist/tree-checklist-example.ts [132:145]


  constructor(private _database: ChecklistDatabase) {
    this.treeFlattener = new MatTreeFlattener(
      this.transformer,
      this.getLevel,
      this.isExpandable,
      this.getChildren,
    );
    this.treeControl = new FlatTreeControl<TodoItemFlatNode>(this.getLevel, this.isExpandable);
    this.dataSource = new MatTreeFlatDataSource(this.treeControl, this.treeFlattener);

    _database.dataChange.subscribe(data => {
      this.dataSource.data = data;
    });
  }