From 488d3d5c2cfe4396371d3c2d78c90d120641f627 Mon Sep 17 00:00:00 2001
From: Dan Percic <dan@devplant.ro>
Date: Thu, 28 Oct 2021 23:05:00 +0300
Subject: [PATCH] add trackBy function

---
 src/lib/listing/models/listable.ts  | 5 +++--
 src/lib/listing/models/trackable.ts | 3 +++
 src/lib/utils/functions.ts          | 5 +++++
 3 files changed, 11 insertions(+), 2 deletions(-)
 create mode 100644 src/lib/listing/models/trackable.ts

diff --git a/src/lib/listing/models/listable.ts b/src/lib/listing/models/listable.ts
index f270290..ead3157 100644
--- a/src/lib/listing/models/listable.ts
+++ b/src/lib/listing/models/listable.ts
@@ -1,5 +1,6 @@
-export interface IListable {
-    readonly id: string;
+import { ITrackable } from './trackable';
+
+export interface IListable extends ITrackable {
     readonly searchKey: string;
     readonly routerLink?: string;
 }
diff --git a/src/lib/listing/models/trackable.ts b/src/lib/listing/models/trackable.ts
new file mode 100644
index 0000000..b752b41
--- /dev/null
+++ b/src/lib/listing/models/trackable.ts
@@ -0,0 +1,3 @@
+export interface ITrackable {
+    readonly id: string;
+}
diff --git a/src/lib/utils/functions.ts b/src/lib/utils/functions.ts
index 1ad6bd7..d4e5451 100644
--- a/src/lib/utils/functions.ts
+++ b/src/lib/utils/functions.ts
@@ -1,4 +1,5 @@
 import { tap } from 'rxjs/operators';
+import { ITrackable } from '../listing/models/trackable';
 
 export function capitalize(value: string): string {
     if (!value) {
@@ -25,3 +26,7 @@ export function toNumber(str: string): number {
         return 0;
     }
 }
+
+export function trackBy() {
+    return <T extends ITrackable>(index: number, item: T): string => item.id;
+}