Slider container: Fix error about observer

sharedComponents/slider-utils/slider-container.component.ts

@@ -60,7 +60,7 @@ export class SliderContainerComponent implements OnInit, OnDestroy, AfterContent
   }
 
   ngOnDestroy() {
-    if(this.observer) {
+    if(this.observer && typeof IntersectionObserver !== 'undefined') {
       this.observer.disconnect();
     }
   }
@@ -78,24 +78,26 @@ export class SliderContainerComponent implements OnInit, OnDestroy, AfterContent
   }
 
   setObserver() {
-    let options = {
-      root: null,
-      rootMargin: '0px',
-      threshold: 0.1
-    };
-    this.observer = new IntersectionObserver(entries => {
-      entries.forEach(entry => {
-        if (entry.isIntersecting && !this.initialized) {
-          this.stopped = false;
-          this.start(0);
-          this.initialized = true;
-        } else {
-          this.initialized = false;
-          this.stopped = true;
-        }
-      });
-    }, options);
-    this.observer.observe(this.element.nativeElement);
+    if(typeof IntersectionObserver !== 'undefined') {
+      let options = {
+        root: null,
+        rootMargin: '0px',
+        threshold: 0.1
+      };
+      this.observer = new IntersectionObserver(entries => {
+        entries.forEach(entry => {
+          if (entry.isIntersecting && !this.initialized) {
+            this.stopped = false;
+            this.start(0);
+            this.initialized = true;
+          } else {
+            this.initialized = false;
+            this.stopped = true;
+          }
+        });
+      }, options);
+      this.observer.observe(this.element.nativeElement);
+    }
   }
 
   start(time: number) {