From 8ba83e73fa88175a46b842fe0f1f0f8bec9b9ba8 Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Wed, 11 Feb 2026 22:37:49 +0100
Subject: [PATCH] Start using `Response.prototype.bytes()` in the code-base

In all cases where we currently use `Response.prototype.arrayBuffer()` the result is immediately wrapped in a `Uint8Array`, which can be avoided by instead using the newer `Response.prototype.bytes()` method; see https://developer.mozilla.org/en-US/docs/Web/API/Response/bytes
---
 src/core/core_utils.js                   |  2 +-
 src/display/cmap_reader_factory.js       |  6 ++----
 src/display/display_utils.js             |  7 ++++++-
 src/display/standard_fontdata_factory.js |  3 +--
 src/display/wasm_factory.js              |  3 +--
 src/shared/util.js                       | 12 ++++++++++++
 test/unit/test_utils.js                  |  3 +--
 7 files changed, 24 insertions(+), 12 deletions(-)

diff --git a/src/core/core_utils.js b/src/core/core_utils.js
index f3218ac61..5980a51f2 100644
--- a/src/core/core_utils.js
+++ b/src/core/core_utils.js
@@ -129,7 +129,7 @@ async function fetchBinaryData(url) {
       `Failed to fetch file "${url}" with "${response.statusText}".`
     );
   }
-  return new Uint8Array(await response.arrayBuffer());
+  return response.bytes();
 }
 
 /**
diff --git a/src/display/cmap_reader_factory.js b/src/display/cmap_reader_factory.js
index 5246fbb23..748bf8812 100644
--- a/src/display/cmap_reader_factory.js
+++ b/src/display/cmap_reader_factory.js
@@ -64,11 +64,9 @@ class DOMCMapReaderFactory extends BaseCMapReaderFactory {
   async _fetch(url) {
     const data = await fetchData(
       url,
-      /* type = */ this.isCompressed ? "arraybuffer" : "text"
+      /* type = */ this.isCompressed ? "bytes" : "text"
     );
-    return data instanceof ArrayBuffer
-      ? new Uint8Array(data)
-      : stringToBytes(data);
+    return data instanceof Uint8Array ? data : stringToBytes(data);
   }
 }
 
diff --git a/src/display/display_utils.js b/src/display/display_utils.js
index 16181b3e5..c8f66a97d 100644
--- a/src/display/display_utils.js
+++ b/src/display/display_utils.js
@@ -48,6 +48,8 @@ async function fetchData(url, type = "text") {
         return response.arrayBuffer();
       case "blob":
         return response.blob();
+      case "bytes":
+        return response.bytes();
       case "json":
         return response.json();
     }
@@ -58,7 +60,7 @@ async function fetchData(url, type = "text") {
   return new Promise((resolve, reject) => {
     const request = new XMLHttpRequest();
     request.open("GET", url, /* async = */ true);
-    request.responseType = type;
+    request.responseType = type === "bytes" ? "arraybuffer" : type;
 
     request.onreadystatechange = () => {
       if (request.readyState !== XMLHttpRequest.DONE) {
@@ -66,6 +68,9 @@ async function fetchData(url, type = "text") {
       }
       if (request.status === 200 || request.status === 0) {
         switch (type) {
+          case "bytes":
+            resolve(new Uint8Array(request.response));
+            return;
           case "arraybuffer":
           case "blob":
           case "json":
diff --git a/src/display/standard_fontdata_factory.js b/src/display/standard_fontdata_factory.js
index bfd8af3c0..15cdfdd23 100644
--- a/src/display/standard_fontdata_factory.js
+++ b/src/display/standard_fontdata_factory.js
@@ -57,8 +57,7 @@ class DOMStandardFontDataFactory extends BaseStandardFontDataFactory {
    * @ignore
    */
   async _fetch(url) {
-    const data = await fetchData(url, /* type = */ "arraybuffer");
-    return new Uint8Array(data);
+    return fetchData(url, /* type = */ "bytes");
   }
 }
 
diff --git a/src/display/wasm_factory.js b/src/display/wasm_factory.js
index 297e8e0e3..cc889e101 100644
--- a/src/display/wasm_factory.js
+++ b/src/display/wasm_factory.js
@@ -55,8 +55,7 @@ class DOMWasmFactory extends BaseWasmFactory {
    * @ignore
    */
   async _fetch(url) {
-    const data = await fetchData(url, /* type = */ "arraybuffer");
-    return new Uint8Array(data);
+    return fetchData(url, /* type = */ "bytes");
   }
 }
 
diff --git a/src/shared/util.js b/src/shared/util.js
index ccbc2f56a..039efa7d6 100644
--- a/src/shared/util.js
+++ b/src/shared/util.js
@@ -1248,6 +1248,18 @@ if (
   };
 }
 
+// See https://developer.mozilla.org/en-US/docs/Web/API/Response/bytes#browser_compatibility
+if (
+  typeof PDFJSDev !== "undefined" &&
+  !PDFJSDev.test("SKIP_BABEL") &&
+  typeof Response.prototype.bytes !== "function"
+) {
+  Response.prototype.bytes = async function () {
+    return new Uint8Array(await this.arrayBuffer());
+  };
+}
+
+// TODO: Remove this once Safari 17.4 is the lowest supported version.
 if (
   typeof PDFJSDev !== "undefined" &&
   !PDFJSDev.test("SKIP_BABEL") &&
diff --git a/test/unit/test_utils.js b/test/unit/test_utils.js
index 15b5fce06..5d59c8f21 100644
--- a/test/unit/test_utils.js
+++ b/test/unit/test_utils.js
@@ -41,8 +41,7 @@ class DefaultFileReaderFactory {
     if (isNodeJS) {
       return fetchDataNode(params.path);
     }
-    const data = await fetchDataDOM(params.path, /* type = */ "arraybuffer");
-    return new Uint8Array(data);
+    return fetchDataDOM(params.path, /* type = */ "bytes");
   }
 }