From 323f326716e90d255d90568cba817271479213c5 Mon Sep 17 00:00:00 2001
From: MrBBot <me@mrbbot.dev>
Date: Sun, 14 Aug 2022 09:28:41 +0100
Subject: [PATCH] fix(File): respect typed array `byteOffset` and `byteLength`
 (#1601)

`File` ignored the `byteOffset` and `byteLength` properties of typed
arrays, meaning the entire backing `ArrayBuffer` was included.
Notably, this caused issues when passing `Buffer`s to the `File`
constructor.
---
 lib/fetch/file.js  |  4 +++-
 test/fetch/file.js | 19 +++++++++++++++++++
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/lib/fetch/file.js b/lib/fetch/file.js
index 647fc5ff38e..be12fb2b584 100644
--- a/lib/fetch/file.js
+++ b/lib/fetch/file.js
@@ -278,7 +278,9 @@ function processBlobParts (parts, options) {
       if (!element.buffer) { // ArrayBuffer
         bytes.push(new Uint8Array(element))
       } else {
-        bytes.push(element.buffer)
+        bytes.push(
+          new Uint8Array(element.buffer, element.byteOffset, element.byteLength)
+        )
       }
     } else if (isBlobLike(element)) {
       // 3. If element is a Blob, append the bytes it represents
diff --git a/test/fetch/file.js b/test/fetch/file.js
index 88e6636ece1..59015413eb0 100644
--- a/test/fetch/file.js
+++ b/test/fetch/file.js
@@ -120,6 +120,16 @@ test('File.prototype.text', async (t) => {
     t.equal(await file.text(), 'hello world')
     t.end()
   })
+
+  t.test('With TypedArray range', async (t) => {
+    const uint8_1 = new Uint8Array(Buffer.from('hello world'))
+    const uint8_2 = new Uint8Array(uint8_1.buffer, 1, 4)
+
+    const file = new File([uint8_2], 'hello_world.txt')
+
+    t.equal(await file.text(), 'ello')
+    t.end()
+  })
   /* eslint-enable camelcase */
 
   t.test('With ArrayBuffer', async (t) => {
@@ -140,6 +150,15 @@ test('File.prototype.text', async (t) => {
     t.end()
   })
 
+  t.test('With Buffer', async (t) => {
+    const buffer = Buffer.from('hello world')
+
+    const file = new File([buffer], 'hello_world.txt')
+
+    t.equal(await file.text(), 'hello world')
+    t.end()
+  })
+
   t.test('Mixed', async (t) => {
     const blob = new Blob(['Hello, '])
     const uint8 = new Uint8Array(Buffer.from('world! This'))