From ebdc34669928ab0b50d2972471d43315a4f67ce3 Mon Sep 17 00:00:00 2001
From: Daniel Macak <daniel.macak@email.cz>
Date: Sun, 17 Dec 2023 18:01:29 +0100
Subject: [PATCH] fix: check that changes are defined

It can easily happen that items are undefined as a change when
ngOnChanges is called in GalleryComponent. This is a deficiency of the
Angular's types that this is not checked, and it slipped through my test
suite as well.

So I created a stricter type that will keep the possibility of changes
being undefined in check and reorganized the test so that the ngOnChanges
with undefined `items` change is checked as well.
---
 .../src/lib/components/gallery/gallery.component.spec.ts    | 2 ++
 .../gallery/src/lib/components/gallery/gallery.component.ts | 6 +++---
 libs/gallery/src/lib/core/ng.ts                             | 6 +++++-
 3 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/libs/gallery/src/lib/components/gallery/gallery.component.spec.ts b/libs/gallery/src/lib/components/gallery/gallery.component.spec.ts
index 7c1fadbf..844cba97 100644
--- a/libs/gallery/src/lib/components/gallery/gallery.component.spec.ts
+++ b/libs/gallery/src/lib/components/gallery/gallery.component.spec.ts
@@ -36,6 +36,8 @@ describe('GalleryComponent', () => {
 
   it('should handle empty items input in looping mode', () => {
     componentRef.setInput('items', undefined);
+    fixture.detectChanges();
+
     componentRef.setInput('loop', true);
     fixture.detectChanges();
 
diff --git a/libs/gallery/src/lib/components/gallery/gallery.component.ts b/libs/gallery/src/lib/components/gallery/gallery.component.ts
index ca0f48b4..415eb547 100644
--- a/libs/gallery/src/lib/components/gallery/gallery.component.ts
+++ b/libs/gallery/src/lib/components/gallery/gallery.component.ts
@@ -9,7 +9,6 @@ import {
   Input,
   OnChanges,
   Output,
-  SimpleChanges,
   TemplateRef,
   ViewChild,
 } from '@angular/core';
@@ -27,6 +26,7 @@ import {
   VerticalOrientation,
 } from '../../core';
 import { defaultAria } from '../../core/aria';
+import { StrictSimpleChanges } from '../../core/ng';
 import { ThumbsComponent } from '../thumbs/thumbs.component';
 import { ViewerComponent } from '../viewer/viewer.component';
 
@@ -191,8 +191,8 @@ export class GalleryComponent implements OnChanges {
       : OrientationFlag.VERTICAL;
   }
 
-  ngOnChanges({ items }: SimpleChanges) {
-    if (!items.currentValue) {
+  ngOnChanges({ items }: StrictSimpleChanges<GalleryComponent>) {
+    if (!items?.currentValue) {
       this.items = [];
     }
   }
diff --git a/libs/gallery/src/lib/core/ng.ts b/libs/gallery/src/lib/core/ng.ts
index 13572fd4..8c152d94 100644
--- a/libs/gallery/src/lib/core/ng.ts
+++ b/libs/gallery/src/lib/core/ng.ts
@@ -1,6 +1,10 @@
-import { ComponentRef } from '@angular/core';
+import { ComponentRef, SimpleChange, SimpleChanges } from '@angular/core';
 
 export interface StrictComponentRef<C> extends ComponentRef<C> {
   // `& string` because otherwise keyof would return string | number
   setInput(name: keyof C & string, value: unknown): void;
 }
+
+export type StrictSimpleChanges<T> = SimpleChanges & {
+  [propName in keyof T]: SimpleChange | undefined;
+};