export default class BreadcrumbsService {
  private _handlers = [];
  private _items = [];
  private _activeItem = '';

  listen(handler) {
    this._handlers.push(handler);
    return () => {
      this._handlers.splice(this._handlers.indexOf(handler), 1);
    };
  }

  _notify() {
    this._handlers.forEach(handler => handler());
  }

  get items() {
    return this._items;
  }

  set items(items) {
    this._items = items;
    this._notify();
  }

  get activeItem() {
    return this._activeItem;
  }

  set activeItem(item) {
    this._activeItem = item;
    this._notify();
  }
}

export default class BreadcrumbsService {
  constructor() {
    this._handlers = [];
    this._items = [];
    this._activeItem = '';
  }

  listen(handler) {
    this._handlers.push(handler);
    return () => {
      this._handlers.splice(this._handlers.indexOf(handler), 1);
    };
  }

  _notify() {
    this._handlers.forEach(handler => handler());
  }

  get items() {
    return this._items;
  }

  set items(items) {
    this._items = items;
    this._notify();
  }

  get activeItem() {
    return this._activeItem;
  }

  set activeItem(item) {
    this._activeItem = item;
    this._notify();
  }
}

--- 
+++ 
@@ -1,9 +1,7 @@
 export default class BreadcrumbsService {
-  constructor() {
-    this._handlers = [];
-    this._items = [];
-    this._activeItem = '';
-  }
+  private _handlers = [];
+  private _items = [];
+  private _activeItem = '';
 
   listen(handler) {
     this._handlers.push(handler);
Fix TypeScript compilation error in BreadcrumbsService.
