From b0a73a9388afad233ea207c9cfeb3cbe132fc5eb Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Wed, 24 Aug 2022 12:10:07 +0200
Subject: [PATCH] Use `AbortController` unconditionally with the Fetch API

Given the browsers that we currently support in the PDF.js project and the MDN compatibility data, see links below, it should no longer be necessary to check for the availability of `AbortController` before using it.
 - https://github.com/mozilla/pdf.js/wiki/Frequently-Asked-Questions#faq-support
 - https://developer.mozilla.org/en-US/docs/Web/API/AbortController#browser_compatibility
---
 src/display/fetch_stream.js | 19 +++++--------------
 1 file changed, 5 insertions(+), 14 deletions(-)

diff --git a/src/display/fetch_stream.js b/src/display/fetch_stream.js
index 5cea226cf..37e15449c 100644
--- a/src/display/fetch_stream.js
+++ b/src/display/fetch_stream.js
@@ -35,7 +35,7 @@ function createFetchOptions(headers, withCredentials, abortController) {
   return {
     method: "GET",
     headers,
-    signal: abortController?.signal,
+    signal: abortController.signal,
     mode: "cors",
     credentials: withCredentials ? "include" : "same-origin",
     redirect: "follow",
@@ -114,9 +114,7 @@ class PDFFetchStreamReader {
       this._disableRange = true;
     }
 
-    if (typeof AbortController !== "undefined") {
-      this._abortController = new AbortController();
-    }
+    this._abortController = new AbortController();
     this._isStreamingSupported = !source.disableStream;
     this._isRangeSupported = !source.disableRange;
 
@@ -207,9 +205,7 @@ class PDFFetchStreamReader {
     if (this._reader) {
       this._reader.cancel(reason);
     }
-    if (this._abortController) {
-      this._abortController.abort();
-    }
+    this._abortController.abort();
   }
 }
 
@@ -224,10 +220,7 @@ class PDFFetchStreamRangeReader {
     this._readCapability = createPromiseCapability();
     this._isStreamingSupported = !source.disableStream;
 
-    if (typeof AbortController !== "undefined") {
-      this._abortController = new AbortController();
-    }
-
+    this._abortController = new AbortController();
     this._headers = createHeaders(this._stream.httpHeaders);
     this._headers.append("Range", `bytes=${begin}-${end - 1}`);
 
@@ -274,9 +267,7 @@ class PDFFetchStreamRangeReader {
     if (this._reader) {
       this._reader.cancel(reason);
     }
-    if (this._abortController) {
-      this._abortController.abort();
-    }
+    this._abortController.abort();
   }
 }