feat(igxPivot): Add aggregatorName property as aggregator alternative.

Author: MKirova

projects/igniteui-angular/src/lib/grids/pivot-grid/pivot-grid-aggregate.ts

@@ -28,7 +28,7 @@ export class IgxPivotAggregate {
      *
      * @memberof IgxPivotAggregate
      */
-    public static aggregators() {
+    public static aggregators(): Array<IPivotAggregator> {
         return [{
             key: 'COUNT',
             label: this.resourceStrings.igx_grid_pivot_aggregate_count,

projects/igniteui-angular/src/lib/grids/pivot-grid/pivot-grid.interface.ts

@@ -57,11 +57,16 @@ export interface IPivotAggregator {
     key: string;
     /** Aggregation label to show in the UI. */
     label: string;
+    /**
+     * Aggregation name that will be used from a list of predefined aggregations.
+     * If not set will use the specified aggregator function.
+     */
+    aggregatorName?: PivotAggregationType;
     /**
      * Aggregator function can be a custom implementation of `PivotAggregation`, or 
      * use predefined ones from `IgxPivotAggregate` and its variants.
      */
-    aggregator: (members: any[], data?: any[]) => any;
+    aggregator?: (members: any[], data?: any[]) => any;
 }
 
 /**
@@ -176,6 +181,8 @@ export enum PivotDimensionType {
     Filter
 }
 
+export type PivotAggregationType = 'SUM' | 'AVG' | 'MIN' | 'MAX' | 'COUNT' | 'LATEST' | 'EARLIEST' ;
+
 /** Interface describing the pivot dimension data.
 * Contains additional information needed to render dimension headers.
 */

projects/igniteui-angular/src/lib/grids/pivot-grid/pivot-util.ts

@@ -233,12 +233,30 @@ export class PivotUtil {
     public static aggregate(records, values: IPivotValue[]) {
         const result = {};
         for (const pivotValue of values) {
-            result[pivotValue.member] = pivotValue.aggregate.aggregator(records.map(r => r[pivotValue.member]), records);
+            const aggregator = PivotUtil.getAggregatorForType(pivotValue.aggregate, pivotValue.dataType);
+            if (!aggregator) {
+                throw "No valid aggregator found for: " + pivotValue.member + ". Please set either a valid aggregatorName or aggregator.";
+            }
+            result[pivotValue.member] = aggregator(records.map(r => r[pivotValue.member]), records);
         }
 
         return result;
     }
 
+    public static getAggregatorForType(aggregate: IPivotAggregator, dataType: GridColumnDataType) {
+        let aggregator = aggregate.aggregator;
+        if (aggregate.aggregatorName) {
+            let aggregators = IgxPivotNumericAggregate.aggregators();
+            if (dataType === 'date' || dataType === 'dateTime') {
+                aggregators = aggregators.concat(IgxPivotDateAggregate.aggregators())
+            } else if (dataType === 'time') {
+                aggregators = aggregators.concat(IgxPivotTimeAggregate.aggregators());
+            }
+            aggregator = aggregators.find(x => x.key === aggregate.aggregatorName)?.aggregator;
+        }
+        return aggregator;
+    }
+
     public static processHierarchy(hierarchies, pivotKeys, level = 0, rootData = false): IPivotGridRecord[] {
         const flatData: IPivotGridRecord[] = [];
         hierarchies.forEach((h, key) => {

src/app/pivot-grid/pivot-grid.sample.ts

@@ -372,7 +372,7 @@ export class PivotGridSampleComponent {
                     member: 'UnitsSold',
                     aggregate: {
                         key: 'SUM',
-                        aggregator: IgxPivotNumericAggregate.sum,
+                        aggregatorName: 'SUM',
                         label: 'Sum'
                     },
                     enabled: true,