From ba77134020705d6c65d7f6f7a2f9fb09c2ea99e7 Mon Sep 17 00:00:00 2001
From: Wojciech Maj <kontakt@wojtekmaj.pl>
Date: Wed, 26 Jun 2024 11:33:54 +0200
Subject: [PATCH] Add explicit function return types

---
 packages/react-pdf/src/Document.spec.tsx      |  8 +++-
 packages/react-pdf/src/Document.tsx           | 11 +++++-
 packages/react-pdf/src/DocumentContext.tsx    |  5 ++-
 packages/react-pdf/src/LinkService.ts         | 38 +++++++++----------
 packages/react-pdf/src/Message.tsx            |  2 +-
 packages/react-pdf/src/Outline.tsx            |  2 +-
 packages/react-pdf/src/OutlineContext.tsx     |  4 +-
 packages/react-pdf/src/OutlineItem.tsx        |  2 +-
 packages/react-pdf/src/Page.tsx               |  2 +-
 .../react-pdf/src/Page/AnnotationLayer.tsx    |  2 +-
 packages/react-pdf/src/Page/Canvas.tsx        |  2 +-
 packages/react-pdf/src/Page/TextLayer.tsx     |  2 +-
 packages/react-pdf/src/PageContext.tsx        |  4 +-
 packages/react-pdf/src/Ref.ts                 |  2 +-
 packages/react-pdf/src/StructTree.tsx         |  2 +-
 packages/react-pdf/src/StructTreeItem.tsx     |  5 ++-
 packages/react-pdf/src/Thumbnail.tsx          |  2 +-
 packages/react-pdf/src/shared/constants.ts    |  2 +-
 .../src/shared/hooks/useDocumentContext.ts    |  4 +-
 .../src/shared/hooks/useOutlineContext.ts     |  4 +-
 .../src/shared/hooks/usePageContext.ts        |  4 +-
 .../react-pdf/src/shared/hooks/useResolver.ts |  2 +-
 packages/react-pdf/src/shared/utils.ts        | 12 +++---
 23 files changed, 75 insertions(+), 48 deletions(-)

diff --git a/packages/react-pdf/src/Document.spec.tsx b/packages/react-pdf/src/Document.spec.tsx
index fb10bde16..e8e9bcb66 100644
--- a/packages/react-pdf/src/Document.spec.tsx
+++ b/packages/react-pdf/src/Document.spec.tsx
@@ -12,6 +12,7 @@ import { makeAsyncCallback, loadPDF, muteConsole, restoreConsole } from '../../.
 
 import type { PDFDocumentProxy } from 'pdfjs-dist';
 import type { ScrollPageIntoViewArgs } from './shared/types.js';
+import type LinkService from './LinkService.js';
 
 const pdfFile = loadPDF('./../../__mocks__/_pdf.pdf');
 const pdfFile2 = loadPDF('./../../__mocks__/_pdf2.pdf');
@@ -433,7 +434,8 @@ describe('Document', () => {
 
       const onItemClick = vi.fn();
       const instance = createRef<{
-        pages: React.RefObject<Record<string, unknown>[]>;
+        linkService: React.RefObject<LinkService>;
+        pages: React.RefObject<HTMLDivElement[]>;
         viewer: React.RefObject<{ scrollPageIntoView: (args: ScrollPageIntoViewArgs) => void }>;
       }>();
 
@@ -473,7 +475,9 @@ describe('Document', () => {
       const { func: onLoadSuccess, promise: onLoadSuccessPromise } = makeAsyncCallback();
 
       const instance = createRef<{
-        pages: React.RefObject<Record<string, unknown>[]>;
+        linkService: React.RefObject<LinkService>;
+        // biome-ignore lint/suspicious/noExplicitAny: Intentional use to simplify the test
+        pages: React.RefObject<any[]>;
         viewer: React.RefObject<{ scrollPageIntoView: (args: ScrollPageIntoViewArgs) => void }>;
       }>();
 
diff --git a/packages/react-pdf/src/Document.tsx b/packages/react-pdf/src/Document.tsx
index bac901484..9de1392f3 100644
--- a/packages/react-pdf/src/Document.tsx
+++ b/packages/react-pdf/src/Document.tsx
@@ -232,7 +232,14 @@ function isParameterObject(file: File): file is Source {
 /**
  * Loads a document passed using `file` prop.
  */
-const Document = forwardRef(function Document(
+const Document: React.ForwardRefExoticComponent<
+  DocumentProps &
+    React.RefAttributes<{
+      linkService: React.RefObject<LinkService>;
+      pages: React.RefObject<HTMLDivElement[]>;
+      viewer: React.RefObject<{ scrollPageIntoView: (args: ScrollPageIntoViewArgs) => void }>;
+    }>
+> = forwardRef(function Document(
   {
     children,
     className,
@@ -255,7 +262,7 @@ const Document = forwardRef(function Document(
     renderMode,
     rotate,
     ...otherProps
-  }: DocumentProps,
+  },
   ref,
 ) {
   const [sourceState, sourceDispatch] = useResolver<Source | null>();
diff --git a/packages/react-pdf/src/DocumentContext.tsx b/packages/react-pdf/src/DocumentContext.tsx
index 2cc037e82..c78ba1175 100644
--- a/packages/react-pdf/src/DocumentContext.tsx
+++ b/packages/react-pdf/src/DocumentContext.tsx
@@ -4,4 +4,7 @@ import { createContext } from 'react';
 
 import type { DocumentContextType } from './shared/types.js';
 
-export default createContext<DocumentContextType>(null);
+const documentContext: React.Context<DocumentContextType> =
+  createContext<DocumentContextType>(null);
+
+export default documentContext;
diff --git a/packages/react-pdf/src/LinkService.ts b/packages/react-pdf/src/LinkService.ts
index 5da83874a..edf7ea316 100644
--- a/packages/react-pdf/src/LinkService.ts
+++ b/packages/react-pdf/src/LinkService.ts
@@ -49,31 +49,31 @@ export default class LinkService implements IPDFLinkService {
     this.pdfViewer = undefined;
   }
 
-  setDocument(pdfDocument: PDFDocumentProxy) {
+  setDocument(pdfDocument: PDFDocumentProxy): void {
     this.pdfDocument = pdfDocument;
   }
 
-  setViewer(pdfViewer: PDFViewer) {
+  setViewer(pdfViewer: PDFViewer): void {
     this.pdfViewer = pdfViewer;
   }
 
-  setExternalLinkRel(externalLinkRel?: ExternalLinkRel) {
+  setExternalLinkRel(externalLinkRel?: ExternalLinkRel): void {
     this.externalLinkRel = externalLinkRel;
   }
 
-  setExternalLinkTarget(externalLinkTarget?: ExternalLinkTarget) {
+  setExternalLinkTarget(externalLinkTarget?: ExternalLinkTarget): void {
     this.externalLinkTarget = externalLinkTarget;
   }
 
-  setHistory() {
+  setHistory(): void {
     // Intentionally empty
   }
 
-  get pagesCount() {
+  get pagesCount(): number {
     return this.pdfDocument ? this.pdfDocument.numPages : 0;
   }
 
-  get page() {
+  get page(): number {
     invariant(this.pdfViewer, 'PDF viewer is not initialized.');
 
     return this.pdfViewer.currentPageNumber || 0;
@@ -85,7 +85,7 @@ export default class LinkService implements IPDFLinkService {
     this.pdfViewer.currentPageNumber = value;
   }
 
-  get rotation() {
+  get rotation(): number {
     return 0;
   }
 
@@ -147,11 +147,11 @@ export default class LinkService implements IPDFLinkService {
     });
   }
 
-  navigateTo(dest: Dest) {
+  navigateTo(dest: Dest): void {
     this.goToDestination(dest);
   }
 
-  goToPage(pageNumber: number) {
+  goToPage(pageNumber: number): void {
     const pageIndex = pageNumber - 1;
 
     invariant(this.pdfViewer, 'PDF viewer is not initialized.');
@@ -167,41 +167,41 @@ export default class LinkService implements IPDFLinkService {
     });
   }
 
-  addLinkAttributes(link: HTMLAnchorElement, url: string, newWindow: boolean) {
+  addLinkAttributes(link: HTMLAnchorElement, url: string, newWindow: boolean): void {
     link.href = url;
     link.rel = this.externalLinkRel || DEFAULT_LINK_REL;
     link.target = newWindow ? '_blank' : this.externalLinkTarget || '';
   }
 
-  getDestinationHash() {
+  getDestinationHash(): string {
     return '#';
   }
 
-  getAnchorUrl() {
+  getAnchorUrl(): string {
     return '#';
   }
 
-  setHash() {
+  setHash(): void {
     // Intentionally empty
   }
 
-  executeNamedAction() {
+  executeNamedAction(): void {
     // Intentionally empty
   }
 
-  cachePageRef() {
+  cachePageRef(): void {
     // Intentionally empty
   }
 
-  isPageVisible() {
+  isPageVisible(): boolean {
     return true;
   }
 
-  isPageCached() {
+  isPageCached(): boolean {
     return true;
   }
 
-  executeSetOCGState() {
+  executeSetOCGState(): void {
     // Intentionally empty
   }
 }
diff --git a/packages/react-pdf/src/Message.tsx b/packages/react-pdf/src/Message.tsx
index 8f735d53f..1973b6e15 100644
--- a/packages/react-pdf/src/Message.tsx
+++ b/packages/react-pdf/src/Message.tsx
@@ -3,6 +3,6 @@ type MessageProps = {
   type: 'error' | 'loading' | 'no-data';
 };
 
-export default function Message({ children, type }: MessageProps) {
+export default function Message({ children, type }: MessageProps): React.ReactElement {
   return <div className={`react-pdf__message react-pdf__message--${type}`}>{children}</div>;
 }
diff --git a/packages/react-pdf/src/Outline.tsx b/packages/react-pdf/src/Outline.tsx
index 5f7fcca3c..910a6618c 100644
--- a/packages/react-pdf/src/Outline.tsx
+++ b/packages/react-pdf/src/Outline.tsx
@@ -64,7 +64,7 @@ export type OutlineProps = {
  *
  * Should be placed inside `<Document />`. Alternatively, it can have `pdf` prop passed, which can be obtained from `<Document />`'s `onLoadSuccess` callback function.
  */
-export default function Outline(props: OutlineProps) {
+export default function Outline(props: OutlineProps): React.ReactElement | null {
   const documentContext = useDocumentContext();
 
   const mergedProps = { ...documentContext, ...props };
diff --git a/packages/react-pdf/src/OutlineContext.tsx b/packages/react-pdf/src/OutlineContext.tsx
index b290706ca..016b44e43 100644
--- a/packages/react-pdf/src/OutlineContext.tsx
+++ b/packages/react-pdf/src/OutlineContext.tsx
@@ -4,4 +4,6 @@ import { createContext } from 'react';
 
 import type { OutlineContextType } from './shared/types.js';
 
-export default createContext<OutlineContextType>(null);
+const outlineContext: React.Context<OutlineContextType> = createContext<OutlineContextType>(null);
+
+export default outlineContext;
diff --git a/packages/react-pdf/src/OutlineItem.tsx b/packages/react-pdf/src/OutlineItem.tsx
index 25041c6f2..897aded7f 100644
--- a/packages/react-pdf/src/OutlineItem.tsx
+++ b/packages/react-pdf/src/OutlineItem.tsx
@@ -18,7 +18,7 @@ type OutlineItemProps = {
   pdf?: PDFDocumentProxy | false;
 };
 
-export default function OutlineItem(props: OutlineItemProps) {
+export default function OutlineItem(props: OutlineItemProps): React.ReactElement {
   const documentContext = useDocumentContext();
 
   const outlineContext = useOutlineContext();
diff --git a/packages/react-pdf/src/Page.tsx b/packages/react-pdf/src/Page.tsx
index 79bfd7317..32ed1b244 100644
--- a/packages/react-pdf/src/Page.tsx
+++ b/packages/react-pdf/src/Page.tsx
@@ -300,7 +300,7 @@ export type PageProps = {
  *
  * Should be placed inside `<Document />`. Alternatively, it can have `pdf` prop passed, which can be obtained from `<Document />`'s `onLoadSuccess` callback function, however some advanced functions like linking between pages inside a document may not be working correctly.
  */
-export default function Page(props: PageProps) {
+export default function Page(props: PageProps): React.ReactElement {
   const documentContext = useDocumentContext();
 
   const mergedProps = { ...documentContext, ...props };
diff --git a/packages/react-pdf/src/Page/AnnotationLayer.tsx b/packages/react-pdf/src/Page/AnnotationLayer.tsx
index dd665c394..9e28e8136 100644
--- a/packages/react-pdf/src/Page/AnnotationLayer.tsx
+++ b/packages/react-pdf/src/Page/AnnotationLayer.tsx
@@ -14,7 +14,7 @@ import { cancelRunningTask } from '../shared/utils.js';
 
 import type { Annotations } from '../shared/types.js';
 
-export default function AnnotationLayer() {
+export default function AnnotationLayer(): React.ReactElement {
   const documentContext = useDocumentContext();
   const pageContext = usePageContext();
 
diff --git a/packages/react-pdf/src/Page/Canvas.tsx b/packages/react-pdf/src/Page/Canvas.tsx
index 6e4652d59..3f7f61d58 100644
--- a/packages/react-pdf/src/Page/Canvas.tsx
+++ b/packages/react-pdf/src/Page/Canvas.tsx
@@ -24,7 +24,7 @@ type CanvasProps = {
   canvasRef?: React.Ref<HTMLCanvasElement>;
 };
 
-export default function Canvas(props: CanvasProps) {
+export default function Canvas(props: CanvasProps): React.ReactElement {
   const pageContext = usePageContext();
 
   invariant(pageContext, 'Unable to find Page context.');
diff --git a/packages/react-pdf/src/Page/TextLayer.tsx b/packages/react-pdf/src/Page/TextLayer.tsx
index dee9d2135..ca9006c06 100644
--- a/packages/react-pdf/src/Page/TextLayer.tsx
+++ b/packages/react-pdf/src/Page/TextLayer.tsx
@@ -17,7 +17,7 @@ function isTextItem(item: TextItem | TextMarkedContent): item is TextItem {
   return 'str' in item;
 }
 
-export default function TextLayer() {
+export default function TextLayer(): React.ReactElement {
   const pageContext = usePageContext();
 
   invariant(pageContext, 'Unable to find Page context.');
diff --git a/packages/react-pdf/src/PageContext.tsx b/packages/react-pdf/src/PageContext.tsx
index 4bdf4d896..28a73b5ae 100644
--- a/packages/react-pdf/src/PageContext.tsx
+++ b/packages/react-pdf/src/PageContext.tsx
@@ -4,4 +4,6 @@ import { createContext } from 'react';
 
 import type { PageContextType } from './shared/types.js';
 
-export default createContext<PageContextType>(null);
+const pageContext: React.Context<PageContextType> = createContext<PageContextType>(null);
+
+export default pageContext;
diff --git a/packages/react-pdf/src/Ref.ts b/packages/react-pdf/src/Ref.ts
index c54110277..876630167 100644
--- a/packages/react-pdf/src/Ref.ts
+++ b/packages/react-pdf/src/Ref.ts
@@ -7,7 +7,7 @@ export default class Ref {
     this.gen = gen;
   }
 
-  toString() {
+  toString(): string {
     let str = `${this.num}R`;
     if (this.gen !== 0) {
       str += this.gen;
diff --git a/packages/react-pdf/src/StructTree.tsx b/packages/react-pdf/src/StructTree.tsx
index 82a0e9754..fd27c343d 100644
--- a/packages/react-pdf/src/StructTree.tsx
+++ b/packages/react-pdf/src/StructTree.tsx
@@ -11,7 +11,7 @@ import { cancelRunningTask } from './shared/utils.js';
 
 import type { StructTreeNodeWithExtraAttributes } from './shared/types.js';
 
-export default function StructTree() {
+export default function StructTree(): React.ReactElement | null {
   const pageContext = usePageContext();
 
   invariant(pageContext, 'Unable to find Page context.');
diff --git a/packages/react-pdf/src/StructTreeItem.tsx b/packages/react-pdf/src/StructTreeItem.tsx
index c32e731b8..361d83566 100644
--- a/packages/react-pdf/src/StructTreeItem.tsx
+++ b/packages/react-pdf/src/StructTreeItem.tsx
@@ -14,7 +14,10 @@ type StructTreeItemProps = {
   node: StructTreeNodeWithExtraAttributes | StructTreeContent;
 };
 
-export default function StructTreeItem({ className, node }: StructTreeItemProps) {
+export default function StructTreeItem({
+  className,
+  node,
+}: StructTreeItemProps): React.ReactElement {
   const attributes = useMemo(() => getAttributes(node), [node]);
 
   // biome-ignore lint/correctness/useExhaustiveDependencies: Looks like a Biome error
diff --git a/packages/react-pdf/src/Thumbnail.tsx b/packages/react-pdf/src/Thumbnail.tsx
index 88fc33d02..76e7c6b25 100644
--- a/packages/react-pdf/src/Thumbnail.tsx
+++ b/packages/react-pdf/src/Thumbnail.tsx
@@ -48,7 +48,7 @@ export type ThumbnailProps = Omit<
  *
  * Should be placed inside `<Document />`. Alternatively, it can have `pdf` prop passed, which can be obtained from `<Document />`'s `onLoadSuccess` callback function.
  */
-export default function Thumbnail(props: ThumbnailProps) {
+export default function Thumbnail(props: ThumbnailProps): React.ReactElement {
   const documentContext = useDocumentContext();
 
   const mergedProps = { ...documentContext, ...props };
diff --git a/packages/react-pdf/src/shared/constants.ts b/packages/react-pdf/src/shared/constants.ts
index ba4810d95..54640494a 100644
--- a/packages/react-pdf/src/shared/constants.ts
+++ b/packages/react-pdf/src/shared/constants.ts
@@ -56,4 +56,4 @@ export const PDF_ROLE_TO_HTML_ROLE = {
   Artifact: null,
 };
 
-export const HEADING_PATTERN = /^H(\d+)$/;
+export const HEADING_PATTERN: RegExp = /^H(\d+)$/;
diff --git a/packages/react-pdf/src/shared/hooks/useDocumentContext.ts b/packages/react-pdf/src/shared/hooks/useDocumentContext.ts
index 428ea9ba0..c180fd69b 100644
--- a/packages/react-pdf/src/shared/hooks/useDocumentContext.ts
+++ b/packages/react-pdf/src/shared/hooks/useDocumentContext.ts
@@ -2,6 +2,8 @@ import { useContext } from 'react';
 
 import DocumentContext from '../../DocumentContext.js';
 
-export default function useDocumentContext() {
+import type { DocumentContextType } from '../types.js';
+
+export default function useDocumentContext(): DocumentContextType {
   return useContext(DocumentContext);
 }
diff --git a/packages/react-pdf/src/shared/hooks/useOutlineContext.ts b/packages/react-pdf/src/shared/hooks/useOutlineContext.ts
index 8ea2877fb..ea30d1d86 100644
--- a/packages/react-pdf/src/shared/hooks/useOutlineContext.ts
+++ b/packages/react-pdf/src/shared/hooks/useOutlineContext.ts
@@ -2,6 +2,8 @@ import { useContext } from 'react';
 
 import OutlineContext from '../../OutlineContext.js';
 
-export default function useOutlineContext() {
+import type { OutlineContextType } from '../types.js';
+
+export default function useOutlineContext(): OutlineContextType {
   return useContext(OutlineContext);
 }
diff --git a/packages/react-pdf/src/shared/hooks/usePageContext.ts b/packages/react-pdf/src/shared/hooks/usePageContext.ts
index dc7e86087..22578488e 100644
--- a/packages/react-pdf/src/shared/hooks/usePageContext.ts
+++ b/packages/react-pdf/src/shared/hooks/usePageContext.ts
@@ -2,6 +2,8 @@ import { useContext } from 'react';
 
 import PageContext from '../../PageContext.js';
 
-export default function usePageContext() {
+import type { PageContextType } from '../types.js';
+
+export default function usePageContext(): PageContextType {
   return useContext(PageContext);
 }
diff --git a/packages/react-pdf/src/shared/hooks/useResolver.ts b/packages/react-pdf/src/shared/hooks/useResolver.ts
index c556b53e1..65c9432f0 100644
--- a/packages/react-pdf/src/shared/hooks/useResolver.ts
+++ b/packages/react-pdf/src/shared/hooks/useResolver.ts
@@ -23,6 +23,6 @@ function reducer<T>(state: State<T>, action: Action<T>): State<T> {
   }
 }
 
-export default function useResolver<T>() {
+export default function useResolver<T>(): [State<T>, React.Dispatch<Action<T>>] {
   return useReducer(reducer<T>, { value: undefined, error: undefined });
 }
diff --git a/packages/react-pdf/src/shared/utils.ts b/packages/react-pdf/src/shared/utils.ts
index db3a4bf04..5abf8dfcf 100644
--- a/packages/react-pdf/src/shared/utils.ts
+++ b/packages/react-pdf/src/shared/utils.ts
@@ -7,12 +7,12 @@ import type { PageCallback } from './types.js';
 /**
  * Checks if we're running in a browser environment.
  */
-export const isBrowser = typeof document !== 'undefined';
+export const isBrowser: boolean = typeof document !== 'undefined';
 
 /**
  * Checks whether we're running from a local file system.
  */
-export const isLocalFileSystem = isBrowser && window.location.protocol === 'file:';
+export const isLocalFileSystem: boolean = isBrowser && window.location.protocol === 'file:';
 
 /**
  * Checks whether a variable is defined.
@@ -83,28 +83,28 @@ export function dataURItoByteString(dataURI: unknown): string {
   return unescape(dataString);
 }
 
-export function getDevicePixelRatio() {
+export function getDevicePixelRatio(): number {
   return (isBrowser && window.devicePixelRatio) || 1;
 }
 
 const allowFileAccessFromFilesTip =
   'On Chromium based browsers, you can use --allow-file-access-from-files flag for debugging purposes.';
 
-export function displayCORSWarning() {
+export function displayCORSWarning(): void {
   warning(
     !isLocalFileSystem,
     `Loading PDF as base64 strings/URLs may not work on protocols other than HTTP/HTTPS. ${allowFileAccessFromFilesTip}`,
   );
 }
 
-export function displayWorkerWarning() {
+export function displayWorkerWarning(): void {
   warning(
     !isLocalFileSystem,
     `Loading PDF.js worker may not work on protocols other than HTTP/HTTPS. ${allowFileAccessFromFilesTip}`,
   );
 }
 
-export function cancelRunningTask(runningTask?: { cancel?: () => void } | null) {
+export function cancelRunningTask(runningTask?: { cancel?: () => void } | null): void {
   if (runningTask?.cancel) runningTask.cancel();
 }