fix(grid): set 0px when hiding all columns #6243

Author: hanastasov

projects/igniteui-angular/src/lib/grids/grid-base.component.ts

@@ -4602,6 +4602,10 @@ export abstract class IgxGridBaseComponent extends DisplayDensityBase implements
             combinedBlocksSize - columnsWithSetWidths.length :
             visibleChildColumns.length - columnsWithSetWidths.length;
 
+        if (!columnsToSize) {
+            return '0px';
+        }
+
         const sumExistingWidths = columnsWithSetWidths
             .reduce((prev, curr) => {
                 const colWidth = curr.width;

projects/igniteui-angular/src/lib/grids/grid/column-hiding.spec.ts

@@ -620,6 +620,9 @@ describe('Column Hiding UI #grid', () => {
             grid.columnList.forEach((col) => col.hidden = true);
             tick(30);
             fix.detectChanges();
+            grid.columnList.forEach((col) => {
+                expect(col.width).toBe('0px');
+            });
             fixEl = fix.nativeElement, gridEl = grid.nativeElement;
 
             tHeadItems = fixEl.querySelector('igx-grid-header-group');