in docs-content/examples-source/material/tree/tree-loadmore/tree-loadmore-example.ts [111:128]
constructor(private _database: LoadmoreDatabase) {
this.treeFlattener = new MatTreeFlattener(
this.transformer,
this.getLevel,
this.isExpandable,
this.getChildren,
);
this.treeControl = new FlatTreeControl<LoadmoreFlatNode>(this.getLevel, this.isExpandable);
this.dataSource = new MatTreeFlatDataSource(this.treeControl, this.treeFlattener);
_database.dataChange.subscribe(data => {
this.dataSource.data = data;
});
_database.initialize();
}