feat(sorters): add a new SortDirectionNumber interface

- to make it easier to declare/use a Sorters

Author: Ghislain Beaulac

src/app/examples/grid-grouping.component.ts

@@ -1,5 +1,5 @@
 import { Component, Injectable, OnInit, OnDestroy } from '@angular/core';
-import { Aggregators, Column, ExportService, FieldType, Formatter, Formatters, GridOption, Sorters  } from './../modules/angular-slickgrid';
+import { Aggregators, Column, ExportService, FieldType, Formatter, Formatters, GridOption, SortDirectionNumber, Sorters  } from './../modules/angular-slickgrid';
 import { Subscription } from 'rxjs/Subscription';
 
 @Injectable()
@@ -127,9 +127,7 @@ export class GridGroupingComponent implements OnInit, OnDestroy {
         new Aggregators.avg('percentComplete'),
         new Aggregators.sum('cost')
       ],
-      comparer: (a, b) => {
-        return Sorters.numeric(a.value, b.value, 1);
-      },
+      comparer: (a, b) => Sorters.numeric(a.value, b.value, SortDirectionNumber.asc),
       aggregateCollapsed: false,
       lazyTotalsCalculation: true
     });

src/app/modules/angular-slickgrid/models/index.ts

@@ -68,5 +68,6 @@ export * from './slickEvent.interface';
 export * from './sortChanged.interface';
 export * from './sortChangedArgs.interface';
 export * from './sortDirection.enum';
+export * from './sortDirectionNumber.enum';
 export * from './sortDirectionString';
 export * from './sorter.interface';

src/app/modules/angular-slickgrid/models/sortDirectionNumber.enum.ts

@@ -0,0 +1,5 @@
+export enum SortDirectionNumber {
+  asc = 1,
+  desc = -1,
+  neutral = 0,
+}

src/app/modules/angular-slickgrid/models/sorter.interface.ts

@@ -1 +1,3 @@
-export type Sorter = (value1: any, value2: any, sortDirection: number) => number;
+import { SortDirectionNumber } from './sortDirectionNumber.enum';
+
+export type Sorter = (value1: any, value2: any, sortDirection: SortDirectionNumber) => number;

src/app/modules/angular-slickgrid/services/sort.service.ts

@@ -1,3 +1,4 @@
+import { SortDirectionNumber } from './../models/sortDirectionNumber.enum';
 import { castToPromise } from './utilities';
 import { Column, FieldType, GridOption, SlickEvent, SortChanged, SortDirection, CurrentSorter, CellArgs, SortDirectionString } from './../models/index';
 import { sortByFieldType } from '../sorters/sorterUtilities';
@@ -149,13 +150,13 @@ export class SortService {
       for (let i = 0, l = sortColumns.length; i < l; i++) {
         const columnSortObj = sortColumns[i];
         if (columnSortObj && columnSortObj.sortCol) {
-          const sortDirection = columnSortObj.sortAsc ? 1 : -1;
+          const sortDirection = columnSortObj.sortAsc ? SortDirectionNumber.asc : SortDirectionNumber.desc;
           const sortField = columnSortObj.sortCol.queryField || columnSortObj.sortCol.queryFieldFilter || columnSortObj.sortCol.field;
           const fieldType = columnSortObj.sortCol.type || FieldType.string;
           const value1 = dataRow1[sortField];
           const value2 = dataRow2[sortField];
           const sortResult = sortByFieldType(value1, value2, fieldType, sortDirection);
-          if (sortResult !== 0) {
+          if (sortResult !== SortDirectionNumber.neutral) {
             return sortResult;
           }
         }