Chore: Desktop: Fix eslint issues and strengthen types in NoteEditor.tsx (#10449)

packages/app-desktop/gui/NoteEditor/utils/useScrollWhenReadyOptions.ts

@@ -0,0 +1,44 @@
+import { RefObject, useCallback, useEffect, useRef, useState } from 'react';
+import { NoteBodyEditorRef, ScrollOptions, ScrollOptionTypes } from './types';
+import usePrevious from '@joplin/lib/hooks/usePrevious';
+import ResourceEditWatcher from '@joplin/lib/services/ResourceEditWatcher';
+import type { EditorScrollPercents } from '../../../app.reducer';
+
+interface Props {
+	noteId: string;
+	selectedNoteHash: string;
+	lastEditorScrollPercents: EditorScrollPercents;
+	editorRef: RefObject<NoteBodyEditorRef>;
+}
+
+const useScrollWhenReadyOptions = ({ noteId, selectedNoteHash, lastEditorScrollPercents, editorRef }: Props) => {
+	const [scrollWhenReady, setScrollWhenReady] = useState<ScrollOptions|null>(null);
+
+	const previousNoteId = usePrevious(noteId);
+	const lastScrollPercentsRef = useRef<EditorScrollPercents>();
+	lastScrollPercentsRef.current = lastEditorScrollPercents;
+
+	useEffect(() => {
+		if (noteId === previousNoteId) return;
+
+		if (editorRef.current) {
+			editorRef.current.resetScroll();
+		}
+
+		const lastScrollPercent = lastScrollPercentsRef.current[noteId] || 0;
+		setScrollWhenReady({
+			type: selectedNoteHash ? ScrollOptionTypes.Hash : ScrollOptionTypes.Percent,
+			value: selectedNoteHash ? selectedNoteHash : lastScrollPercent,
+		});
+
+		void ResourceEditWatcher.instance().stopWatchingAll();
+	}, [noteId, previousNoteId, selectedNoteHash, editorRef]);
+
+	const clearScrollWhenReady = useCallback(() => {
+		setScrollWhenReady(null);
+	}, []);
+
+	return { scrollWhenReady, clearScrollWhenReady };
+};
+
+export default useScrollWhenReadyOptions;