Merge pull request #1535 from 4Science/CST-5316-browse-by-issue-date

[CST-5316] "Browsing by issue date" is stuck on loading

src/app/browse-by/browse-by-date-page/browse-by-date-page.component.ts

@@ -18,6 +18,7 @@ import { PaginationService } from '../../core/pagination/pagination.service';
 import { map } from 'rxjs/operators';
 import { PaginationComponentOptions } from '../../shared/pagination/pagination-component-options.model';
 import { SortDirection, SortOptions } from '../../core/cache/models/sort-options.model';
+import { isValidDate } from '../../shared/date.util';
 
 @Component({
   selector: 'ds-browse-by-date-page',
@@ -85,10 +86,10 @@ export class BrowseByDatePageComponent extends BrowseByMetadataPageComponent {
         let lowerLimit = environment.browseBy.defaultLowerLimit;
         if (hasValue(firstItemRD.payload)) {
           const date = firstItemRD.payload.firstMetadataValue(metadataKeys);
-          if (hasValue(date)) {
+          if (isNotEmpty(date) && isValidDate(date)) {
             const dateObj = new Date(date);
             // TODO: it appears that getFullYear (based on local time) is sometimes unreliable. Switching to UTC.
-            lowerLimit = dateObj.getUTCFullYear();
+            lowerLimit = isNaN(dateObj.getUTCFullYear()) ? lowerLimit : dateObj.getUTCFullYear();
           }
         }
         const options = [];

src/app/shared/date.util.ts

@@ -113,3 +113,11 @@ export function dateToString(date: Date | NgbDateStruct): string {
   const dateStr = `${year}-${month}-${day}`;
   return moment.utc(dateStr, 'YYYYMMDD').format('YYYY-MM-DD');
 }
+
+/**
+ * Checks if the given string represents a valid date
+ * @param date the string to be checked
+ */
+export function isValidDate(date: string) {
+  return moment(date).isValid();
+}