From ecf95e552ffab723eafde2eadbbef77290a9e0d6 Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Wed, 26 Jul 2023 09:19:03 +0200
Subject: [PATCH 1/2] Simplify handling of any `ViewHistory` errors during
 document loading in the viewer

We can use modern JavaScript features, in this case optional chaining, to (ever so slightly) simplify how `ViewHistory` errors are handled.

Also, use arrow functions when handling a few other (very rare) errors during loading since that's a tiny bit shorter.
---
 web/app.js | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/web/app.js b/web/app.js
index 355e36c48..c70e3ee96 100644
--- a/web/app.js
+++ b/web/app.js
@@ -1289,13 +1289,13 @@ const PDFViewerApplication = {
 
     // Since the `setInitialView` call below depends on this being resolved,
     // fetch it early to avoid delaying initial rendering of the PDF document.
-    const pageLayoutPromise = pdfDocument.getPageLayout().catch(function () {
+    const pageLayoutPromise = pdfDocument.getPageLayout().catch(() => {
       /* Avoid breaking initial rendering; ignoring errors. */
     });
-    const pageModePromise = pdfDocument.getPageMode().catch(function () {
+    const pageModePromise = pdfDocument.getPageMode().catch(() => {
       /* Avoid breaking initial rendering; ignoring errors. */
     });
-    const openActionPromise = pdfDocument.getOpenAction().catch(function () {
+    const openActionPromise = pdfDocument.getOpenAction().catch(() => {
       /* Avoid breaking initial rendering; ignoring errors. */
     });
 
@@ -1336,7 +1336,6 @@ const PDFViewerApplication = {
       })
       .catch(() => {
         /* Unable to read from storage; ignoring errors. */
-        return Object.create(null);
       });
 
     firstPagePromise.then(pdfPage => {
@@ -1369,7 +1368,7 @@ const PDFViewerApplication = {
           let scrollMode = AppOptions.get("scrollModeOnLoad");
           let spreadMode = AppOptions.get("spreadModeOnLoad");
 
-          if (stored.page && viewOnLoad !== ViewOnLoad.INITIAL) {
+          if (stored?.page && viewOnLoad !== ViewOnLoad.INITIAL) {
             hash =
               `page=${stored.page}&zoom=${zoom || stored.zoom},` +
               `${stored.scrollLeft},${stored.scrollTop}`;

From 2fbfd9517f52c6ec1a1964bf0c4f73d794f362e5 Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Wed, 26 Jul 2023 10:39:51 +0200
Subject: [PATCH 2/2] Remove the unneeded error-handling at the end of
 `PDFViewerApplication.run`

This is quite old code, however the error-handling no longer seems necessary for a couple of reasons:
 - The `PDFViewerApplication.open` method is asynchronous, which means that it cannot throw a "raw" `Error` and the try-catch is not needed in that case.
 - None of the other affected methods should throw, and if they do that'd rather indicate an *implementation* error in the code.
 - Finally, and most importantly, with the `PDFViewerApplication.run` method now being asynchronous an (unlikely) `Error` thrown within it will lead to a rejected `Promise` and not affect execution of other code.
---
 web/app.js | 26 ++++++++++----------------
 1 file changed, 10 insertions(+), 16 deletions(-)

diff --git a/web/app.js b/web/app.js
index c70e3ee96..f4489e956 100644
--- a/web/app.js
+++ b/web/app.js
@@ -694,7 +694,7 @@ const PDFViewerApplication = {
   async run(config) {
     await this.initialize(config);
 
-    const { appConfig, eventBus, l10n } = this;
+    const { appConfig, eventBus } = this;
     let file;
     if (typeof PDFJSDev === "undefined" || PDFJSDev.test("GENERIC")) {
       const queryString = document.location.search.substring(1);
@@ -745,7 +745,7 @@ const PDFViewerApplication = {
 
     if (!this.supportsDocumentFonts) {
       AppOptions.set("disableFontFace", true);
-      l10n.get("web_fonts_disabled").then(msg => {
+      this.l10n.get("web_fonts_disabled").then(msg => {
         console.warn(msg);
       });
     }
@@ -775,22 +775,16 @@ const PDFViewerApplication = {
       true
     );
 
-    try {
-      if (typeof PDFJSDev === "undefined" || PDFJSDev.test("GENERIC")) {
-        if (file) {
-          this.open({ url: file });
-        } else {
-          this._hideViewBookmark();
-        }
-      } else if (PDFJSDev.test("MOZCENTRAL || CHROME")) {
-        this.initPassiveLoading(file);
+    if (typeof PDFJSDev === "undefined" || PDFJSDev.test("GENERIC")) {
+      if (file) {
+        this.open({ url: file });
       } else {
-        throw new Error("Not implemented: run");
+        this._hideViewBookmark();
       }
-    } catch (reason) {
-      l10n.get("loading_error").then(msg => {
-        this._documentError(msg, reason);
-      });
+    } else if (PDFJSDev.test("MOZCENTRAL || CHROME")) {
+      this.initPassiveLoading(file);
+    } else {
+      throw new Error("Not implemented: run");
     }
   },