fix(grid): Fix calculate height when initially grid has no data #3950

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

@@ -3528,7 +3528,7 @@ export abstract class IgxGridBaseComponent extends DisplayDensityBase implements
      * Sets this._height
      */
     protected _derivePossibleHeight() {
-        if ((this._height && this._height.indexOf('%') === -1) || !this._height || !this.isAttachedToDom) {
+        if ((this._height && this._height.indexOf('%') === -1) || !this._height || !this.isAttachedToDom || this.rowBasedHeight === 0) {
             return;
         }
         if (!this.nativeElement.parentNode || !this.nativeElement.parentNode.clientHeight) {

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

@@ -275,26 +275,31 @@ describe('IgxGrid Component Tests', () => {
 
             const grid = fixture.componentInstance.grid;
             const gridBody = fixture.debugElement.query(By.css(TBODY_CLASS));
+            const domGrid = fixture.debugElement.query(By.css('igx-grid')).nativeElement;
+
+            // make sure default width/height are applied when there is no data
+            expect(domGrid.style.height).toBe('100%');
+            expect(domGrid.style.width).toBe('100%');
 
             // Check for loaded rows in grid's container
             fixture.componentInstance.generateData(30);
             fixture.detectChanges();
             tick(1000);
-            expect(parseInt(window.getComputedStyle(gridBody.nativeElement).height, 10)).toBeGreaterThan(1000);
+            expect(parseInt(window.getComputedStyle(gridBody.nativeElement).height, 10)).toBe(548);
 
             // Check for empty filter grid message and body less than 100px
             const columns = fixture.componentInstance.grid.columns;
             grid.filter(columns[0].field, 546000, IgxNumberFilteringOperand.instance().condition('equals'));
             fixture.detectChanges();
             tick(100);
             expect(gridBody.nativeElement.textContent).toEqual(grid.emptyFilteredGridMessage);
-            expect(parseInt(window.getComputedStyle(gridBody.nativeElement).height, 10)).toBeLessThan(100);
+            expect(parseInt(window.getComputedStyle(gridBody.nativeElement).height, 10)).toBe(548);
 
             // Clear filter and check if grid's body height is restored based on all loaded rows
             grid.clearFilter(columns[0].field);
             fixture.detectChanges();
             tick(100);
-            expect(parseInt(window.getComputedStyle(gridBody.nativeElement).height, 10)).toBeGreaterThan(1000);
+            expect(parseInt(window.getComputedStyle(gridBody.nativeElement).height, 10)).toBe(548);
 
             // Clearing grid's data and check for empty grid message
             fixture.componentInstance.clearData();