1 files changed, 63 insertions, 0 deletions
diff --git a/sdc-workflow-designer-ui/src/app/paletx/core/overlay/scroll/scrollable.ts b/sdc-workflow-designer-ui/src/app/paletx/core/overlay/scroll/scrollable.ts
new file mode 100644
index 00000000..fe7b041c
--- /dev/null
+++ b/sdc-workflow-designer-ui/src/app/paletx/core/overlay/scroll/scrollable.ts
@@ -0,0 +1,63 @@
+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+/* tslint:disable:array-type member-access variable-name typedef
+ only-arrow-functions directive-class-suffix component-class-suffix
+ component-selector*/
+import {Directive, ElementRef, NgZone, OnDestroy, OnInit, Renderer2} from '@angular/core';
+import {Observable} from 'rxjs/Observable';
+import {Subject} from 'rxjs/Subject';
+
+import {ScrollDispatcher} from './scroll-dispatcher';
+
+
+/**
+ * Sends an event when the directive's element is scrolled. Registers itself
+ * with the ScrollDispatcher service to include itself as part of its collection
+ * of scrolling events that it can be listened to through the service.
+ */
+@Directive({selector: '[cdk-scrollable], [cdkScrollable]'})
+export class Scrollable implements OnInit, OnDestroy {
+  private _elementScrolled: Subject<Event> = new Subject();
+  private _scrollListener: Function|null;
+
+  constructor(
+		private _elementRef: ElementRef, private _scroll: ScrollDispatcher,
+		private _ngZone: NgZone, private _renderer: Renderer2) {}
+
+  ngOnInit() {
+	this._scrollListener = this._ngZone.runOutsideAngular(() => {
+		return this._renderer.listen(
+			this.getElementRef().nativeElement, 'scroll', (event: Event) => {
+			this._elementScrolled.next(event);
+			});
+	});
+
+	this._scroll.register(this);
+  }
+
+  ngOnDestroy() {
+	this._scroll.deregister(this);
+
+	if (this._scrollListener) {
+		this._scrollListener();
+		this._scrollListener = null;
+	}
+  }
+
+  /**
+   * Returns observable that emits when a scroll event is fired on the host
+   * element.
+   */
+  elementScrolled(): Observable<any> {
+	return this._elementScrolled.asObservable();
+  }
+
+  getElementRef(): ElementRef {
+	return this._elementRef;
+  }
+}