fix(template): virtual-for: properly calculate stable state

hoebbelsB · hoebbelsB · commit 112a299c1d9d · 2024-05-24T22:12:15.000+02:00
diff --git a/libs/template/experimental/virtual-scrolling/src/lib/scroll-strategies/autosize-virtual-scroll-strategy.ts b/libs/template/experimental/virtual-scrolling/src/lib/scroll-strategies/autosize-virtual-scroll-strategy.ts
@@ -359,8 +359,11 @@ export class AutoSizeVirtualScrollStrategy<
   }
 
   private scrollTo(scrollTo: number, behavior?: ScrollBehavior): void {
-    this.waitForScroll = true;
-    this.isStable$.next(false);
+    this.waitForScroll =
+      scrollTo !== this.scrollTop && this.contentSize > this.containerSize;
+    if (this.waitForScroll) {
+      this.isStable$.next(false);
+    }
     this.viewport!.scrollTo(this.viewportOffset + scrollTo, behavior);
   }
 
diff --git a/libs/template/experimental/virtual-scrolling/src/lib/scroll-strategies/dynamic-size-virtual-scroll-strategy.ts b/libs/template/experimental/virtual-scrolling/src/lib/scroll-strategies/dynamic-size-virtual-scroll-strategy.ts
@@ -284,8 +284,11 @@ export class DynamicSizeVirtualScrollStrategy<
     for (let i = 0; i < _index; i++) {
       scrollTo += this._virtualItems[i].size;
     }
-    this.waitForScroll = true;
-    this.isStable$.next(false);
+    this.waitForScroll =
+      scrollTo !== this.scrollTop && this.contentSize > this.containerSize;
+    if (this.waitForScroll) {
+      this.isStable$.next(false);
+    }
     this.viewport!.scrollTo(this.viewportOffset + scrollTo, behavior);
   }
 

Original file line number	Diff line number	Diff line change
`@@ -359,8 +359,11 @@ export class AutoSizeVirtualScrollStrategy<`
`359`	`359`	`}`
`360`	`360`
`361`	`361`	`private scrollTo(scrollTo: number, behavior?: ScrollBehavior): void {`
`362`		`- this.waitForScroll = true;`
`363`		`- this.isStable$.next(false);`
	`362`	`+ this.waitForScroll =`
	`363`	`+ scrollTo !== this.scrollTop && this.contentSize > this.containerSize;`
	`364`	`+ if (this.waitForScroll) {`
	`365`	`+ this.isStable$.next(false);`
	`366`	`+ }`
`364`	`367`	`this.viewport!.scrollTo(this.viewportOffset + scrollTo, behavior);`
`365`	`368`	`}`
`366`	`369`
Original file line number	Diff line number	Diff line change
`@@ -284,8 +284,11 @@ export class DynamicSizeVirtualScrollStrategy<`
`284`	`284`	`for (let i = 0; i < _index; i++) {`
`285`	`285`	`scrollTo += this._virtualItems[i].size;`
`286`	`286`	`}`
`287`		`- this.waitForScroll = true;`
`288`		`- this.isStable$.next(false);`
	`287`	`+ this.waitForScroll =`
	`288`	`+ scrollTo !== this.scrollTop && this.contentSize > this.containerSize;`
	`289`	`+ if (this.waitForScroll) {`
	`290`	`+ this.isStable$.next(false);`
	`291`	`+ }`
`289`	`292`	`this.viewport!.scrollTo(this.viewportOffset + scrollTo, behavior);`
`290`	`293`	`}`
`291`	`294`