refactor: move scroll state into native state

Author: mdjastrzebski

src/native-state.ts

@@ -1,4 +1,5 @@
 import { ReactTestInstance } from 'react-test-renderer';
+import { ContentOffset } from './types';
 
 /**
  * Simulated native state for unmanaged controls.
@@ -7,13 +8,15 @@ import { ReactTestInstance } from 'react-test-renderer';
  */
 export type NativeState = {
   elementValues: WeakMap<ReactTestInstance, string>;
+  scrollPositions: WeakMap<ReactTestInstance, ContentOffset>;
 };
 
 export let nativeState: NativeState | null = null;
 
 export function initNativeState(): void {
   nativeState = {
     elementValues: new WeakMap(),
+    scrollPositions: new WeakMap(),
   };
 }
 

src/types.ts

@@ -1,3 +1,11 @@
+/**
+ * Scroll position of a scrollable element.
+ */
+export interface ContentOffset {
+  y: number;
+  x: number;
+}
+
 // TS autocomplete trick
 // Ref: https://github.com/microsoft/TypeScript/issues/29729#issuecomment-567871939
 export type StringWithAutocomplete<T> = T | (string & {});

src/user-event/event-builder/scroll-view.ts

@@ -1,13 +1,6 @@
+import { ContentOffset } from '../../types';
 import { baseSyntheticEvent } from './base';
 
-/**
- * Scroll position of a scrollable element.
- */
-export interface ContentOffset {
-  y: number;
-  x: number;
-}
-
 /**
  * Other options for constructing a scroll event.
  */

src/user-event/scroll/scroll-to.ts

@@ -5,10 +5,10 @@ import { EventBuilder } from '../event-builder';
 import { ErrorWithStack } from '../../helpers/errors';
 import { isHostScrollView } from '../../helpers/host-component-names';
 import { pick } from '../../helpers/object';
-import { ContentOffset } from '../event-builder/scroll-view';
+import { nativeState } from '../../native-state';
+import { ContentOffset } from '../../types';
 import { dispatchEvent, wait } from '../utils';
 import { createScrollSteps, inertialInterpolator, linearInterpolator } from './utils';
-import { getElementScrollOffset, setElementScrollOffset } from './state';
 
 interface CommonScrollToOptions {
   contentSize?: {
@@ -62,7 +62,7 @@ export async function scrollTo(
     options.contentSize?.height ?? 0,
   );
 
-  const initialPosition = getElementScrollOffset(element);
+  const initialPosition = nativeState?.scrollPositions.get(element) ?? { x: 0, y: 0 };
   const dragSteps = createScrollSteps(
     { y: options.y, x: options.x },
     initialPosition,
@@ -79,7 +79,7 @@ export async function scrollTo(
   await emitMomentumScrollEvents(this.config, element, momentumSteps, options);
 
   const finalPosition = momentumSteps.at(-1) ?? dragSteps.at(-1) ?? initialPosition;
-  setElementScrollOffset(element, finalPosition);
+  nativeState?.scrollPositions.set(element, finalPosition);
 }
 
 async function emitDragScrollEvents(

src/user-event/scroll/state.ts

@@ -1,4 +1,4 @@
-import { ContentOffset } from '../event-builder/scroll-view';
+import { ContentOffset } from '../../types';
 
 const DEFAULT_STEPS_COUNT = 5;