fix(adv-filtering): added header name property to filtering expression #5993

(cherry picked from commit 094cf65)

Author: igdmdimitrov

projects/igniteui-angular/src/lib/data-operations/filtering-expression.interface.ts

@@ -10,6 +10,7 @@ export enum FilteringLogic {
  */
 export declare interface IFilteringExpression {
     fieldName: string;
+    headerName?: string;
     condition: IFilteringOperation;
     searchVal?: any;
     ignoreCase?: boolean;

projects/igniteui-angular/src/lib/grids/filtering/advanced-filtering/advanced-filtering-dialog.component.html

@@ -99,7 +99,7 @@ <h6 class="igx-filter-empty__title">
                           (onRemove)="onChipRemove(expressionItem)"
                           (onSelectionDone)="onChipSelectionEnd()"
                     >
-                    <span igxPrefix class="igx-filter-tree__expression-column">{{ expressionItem.expression.fieldName }}</span>
+                    <span igxPrefix class="igx-filter-tree__expression-column">{{ expressionItem.expression.headerName || expressionItem.expression.fieldName }}</span>
                     <igx-icon
                         igxPrefix
                         fontSet="filtering-icons"

projects/igniteui-angular/src/lib/grids/filtering/advanced-filtering/advanced-filtering-dialog.component.ts

@@ -468,6 +468,7 @@ export class IgxAdvancedFilteringDialogComponent implements AfterViewInit, OnDes
     public commitOperandEdit() {
         if (this.editedExpression) {
             this.editedExpression.expression.fieldName = this.selectedColumn.field;
+            this.editedExpression.expression.headerName = this.selectedColumn.header;
             this.editedExpression.expression.condition = this.selectedColumn.filters.condition(this.selectedCondition);
             this.editedExpression.expression.searchVal = DataUtil.parseValue(this.selectedColumn.dataType, this.searchValue);
 
@@ -563,6 +564,7 @@ export class IgxAdvancedFilteringDialogComponent implements AfterViewInit, OnDes
                     const filteringExpr = expr as IFilteringExpression;
                     const exprCopy: IFilteringExpression = {
                         fieldName: filteringExpr.fieldName,
+                        headerName: filteringExpr.headerName,
                         condition: filteringExpr.condition,
                         searchVal: filteringExpr.searchVal,
                         ignoreCase: filteringExpr.ignoreCase

src/app/grid-filtering/grid-filtering.sample.html

@@ -31,7 +31,7 @@
                 exportExcelText="Export to Excel" 
                 exportCsvText="Export to CSV">
                 <igx-column *ngFor="let c of columns" [field]="c.field"
-                                                    [header]="c.field"
+                                                    [header]="c.header"
                                                     [movable]="c.movable"
                                                     [groupable]="true"
                                                     [resizable]="c.resizable"