Using SortOrder as argument to better convey the possible values

Author: CALABRO Raphael (UA 2118)

src/DataTable.ts

@@ -53,10 +53,10 @@ export class DataTable implements OnChanges, DoCheck {
         return {sortBy: this.sortBy, sortOrder: this.sortOrder};
     }
 
-    public setSort(sortBy: string|string[], sortOrder: string): void {
+    public setSort(sortBy: string|string[], sortOrder: SortOrder): void {
         if (this.sortBy !== sortBy || this.sortOrder !== sortOrder) {
             this.sortBy = sortBy;
-            this.sortOrder = ["asc","desc"].indexOf(sortOrder) >= 0 ? sortOrder as SortOrder : "asc";
+            this.sortOrder = ["asc","desc"].indexOf(sortOrder) >= 0 ? sortOrder : "asc";
             this.mustRecalculateData = true;
             this.onSortChange.next({sortBy: sortBy, sortOrder: sortOrder});
             this.sortByChange.emit(this.sortBy);