From 322b1072afa14c243ea443bda5044981747dede0 Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Sat, 31 Oct 2020 11:24:39 +0100
Subject: [PATCH] Use optional chaining in `web/pdf_history.js`

Since we're now free to use e.g. optional chaining everywhere *except* for the worker, we can thus simplify this code a bit.
---
 web/pdf_history.js | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/web/pdf_history.js b/web/pdf_history.js
index 51e6038fd156d..a4e86774158f9 100644
--- a/web/pdf_history.js
+++ b/web/pdf_history.js
@@ -290,7 +290,7 @@ class PDFHistory {
       return;
     }
 
-    if (this._destination && this._destination.page === pageNumber) {
+    if (this._destination?.page === pageNumber) {
       // When the new page is identical to the one in `this._destination`, we
       // don't want to add a potential duplicate entry in the browser history.
       return;
@@ -388,8 +388,7 @@ class PDFHistory {
     if (
       typeof PDFJSDev !== "undefined" &&
       PDFJSDev.test("CHROME") &&
-      window.history.state &&
-      window.history.state.chromecomState
+      window.history.state?.chromecomState
     ) {
       // history.state.chromecomState is managed by chromecom.js.
       newState.chromecomState = window.history.state.chromecomState;
@@ -397,7 +396,7 @@ class PDFHistory {
     this._updateInternalState(destination, newState.uid);
 
     let newUrl;
-    if (this._updateUrl && destination && destination.hash) {
+    if (this._updateUrl && destination?.hash) {
       const baseUrl = document.location.href.split("#")[0];
       // Prevent errors in Firefox.
       if (!baseUrl.startsWith("file://")) {
@@ -494,7 +493,7 @@ class PDFHistory {
           return false;
         }
         const [perfEntry] = performance.getEntriesByType("navigation");
-        if (!perfEntry || perfEntry.type !== "reload") {
+        if (perfEntry?.type !== "reload") {
           return false;
         }
       } else {
@@ -523,7 +522,7 @@ class PDFHistory {
       clearTimeout(this._updateViewareaTimeout);
       this._updateViewareaTimeout = null;
     }
-    if (removeTemporary && destination && destination.temporary) {
+    if (removeTemporary && destination?.temporary) {
       // When the `destination` comes from the browser history,
       // we no longer treat it as a *temporary* position.
       delete destination.temporary;
@@ -633,8 +632,7 @@ class PDFHistory {
     if (
       (typeof PDFJSDev !== "undefined" &&
         PDFJSDev.test("CHROME") &&
-        state &&
-        state.chromecomState &&
+        state?.chromecomState &&
         !this._isValidState(state)) ||
       !state
     ) {