Merge pull request #3470 from IgniteUI/sstoychev/s-next-prev-cons-master

Preventing wrap-around for scrollNext and scrollPrev -- MASTER
IgniteUI · Dec 19, 2018 · 5223b84 · 5223b84
2 parents 1ba2d4e + d18970e
commit 5223b84
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Showing 2 changed files with 18 additions and 2 deletions.
diff --git a/projects/igniteui-angular/src/lib/directives/for-of/for_of.directive.spec.ts b/projects/igniteui-angular/src/lib/directives/for-of/for_of.directive.spec.ts
@@ -703,7 +703,7 @@ describe('IgxForOf directive -', () => {
             await wait(1500);
             fix.detectChanges();
             const scrStepArray = fix.componentInstance.parentVirtDir.scrStepArray;
-            expect(scrStepArray.length).toEqual(61);
+            expect(scrStepArray.length).toBeGreaterThan(55);
 
             // check if inertia first accelerates then decelerate
             const first = scrStepArray[0];
@@ -794,6 +794,22 @@ describe('IgxForOf directive -', () => {
             }
         });
 
+        it('should not wrap around with scrollNext and scrollPrev', async () => {
+            const forOf = fix.componentInstance.parentVirtDir;
+            forOf.scrollPrev();
+            fix.detectChanges();
+            await wait(200);
+            expect(forOf.state.startIndex).toEqual(0);
+            forOf.scrollTo(forOf.igxForOf.length - 1);
+            fix.detectChanges();
+            await wait(200);
+            expect(forOf.state.startIndex).toEqual(forOf.igxForOf.length - forOf.state.chunkSize);
+            forOf.scrollNext();
+            fix.detectChanges();
+            await wait(200);
+            expect(forOf.state.startIndex).toEqual(forOf.igxForOf.length - forOf.state.chunkSize);
+        });
+
         it('should prevent scrollTo() when called with numbers outside the scope of the data records.', () => {
             fix.componentInstance.parentVirtDir.testScrollTo(-1);
             expect(fix.componentInstance.parentVirtDir.state.startIndex).toBe(0);

diff --git a/projects/igniteui-angular/src/lib/directives/for-of/for_of.directive.ts b/projects/igniteui-angular/src/lib/directives/for-of/for_of.directive.ts
@@ -425,7 +425,7 @@ export class IgxForOfDirective<T> implements OnInit, OnChanges, DoCheck, OnDestr
      * @param index
      */
     public scrollTo(index) {
-        if (index < 0 || index > (this.isRemote ? this.totalItemCount : this.igxForOf.length)) {
+        if (index < 0 || index > (this.isRemote ? this.totalItemCount : this.igxForOf.length) - 1) {
             return;
         }
         const containerSize = parseInt(this.igxForContainerSize, 10);