fix(tree-grid): avoid initial error with summary & no data

Author: damyanpetev

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

@@ -3297,7 +3297,7 @@ export class IgxGridPerformanceComponent implements AfterViewInit, OnInit {
     template: `
         <igx-grid>
             <igx-column field="ID"></igx-column>
-            <igx-column field="Name"></igx-column>
+            <igx-column field="Name" [hasSummary]="true"></igx-column>
             <igx-paginator></igx-paginator>
         </igx-grid>
     `

projects/igniteui-angular/src/lib/grids/tree-grid/tree-grid-api.service.ts

@@ -23,9 +23,9 @@ export class IgxTreeGridAPIService extends GridBaseAPIService<GridType> {
 
     public get_summary_data() {
         const grid = this.grid;
-        const data = grid.processedRootRecords.filter(row => row.isFilteredOutParent === undefined || row.isFilteredOutParent === false)
+        const data = grid.processedRootRecords?.filter(row => row.isFilteredOutParent === undefined || row.isFilteredOutParent === false)
             .map(rec => rec.data);
-        if (grid.transactions.enabled) {
+        if (data && grid.transactions.enabled) {
             const deletedRows = grid.transactions.getTransactionLog().filter(t => t.type === TransactionType.DELETE).map(t => t.id);
             deletedRows.forEach(rowID => {
                 const tempData = grid.primaryKey ? data.map(rec => rec[grid.primaryKey]) : data;

projects/igniteui-angular/src/lib/test-utils/tree-grid-components.spec.ts

@@ -175,8 +175,8 @@ export class IgxTreeGridCellSelectionComponent {
         width="900px" height="500px">
         <igx-column [field]="'ID'" dataType="number"></igx-column>
         <igx-column [field]="'Name'" dataType="string"></igx-column>
-        <igx-column [field]="'HireDate'" dataType="date"></igx-column>
-        <igx-column [field]="'Age'" dataType="number"></igx-column>
+        <igx-column [field]="'HireDate'" dataType="date" [hasSummary]="true"></igx-column>
+        <igx-column [field]="'Age'" dataType="number" [hasSummary]="true"></igx-column>
         <igx-paginator [perPage]="10"></igx-paginator>
     </igx-tree-grid>
     `