From fd632f53c76b8791aee4d85ca50c9aca17833a2f Mon Sep 17 00:00:00 2001
From: Marius Reimer <reime005@gmail.com>
Date: Mon, 10 Dec 2018 16:56:56 -0800
Subject: [PATCH] set blob as default XMLHttpRequest header response type if
 supported (#22063)

Summary:
This is a problem that is discussed in issue #21092

Related issues: #21851 #19717

Found the code to eventually fix this issue [here](https://github.com/github/fetch/blob/899b155746630c32d83ee29a38642da16b314ecb/fetch.js#L486)

- [x] Fetching an image locally and check if the blob is there, as well as its size > 0.

___
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[GENERAL] [ENHANCEMENT] [whatwg-fetch] - set blob as default XMLHttpRequest header response type if supported
Pull Request resolved: https://github.com/facebook/react-native/pull/22063

Differential Revision: D13408797

Pulled By: cpojer

fbshipit-source-id: 9822d5a7e24bacd72838f3fc9a61b1a97b44484b
---
 Libraries/vendor/core/whatwg-fetch.js | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Libraries/vendor/core/whatwg-fetch.js b/Libraries/vendor/core/whatwg-fetch.js
index febc54dac8dd84..19591001401409 100644
--- a/Libraries/vendor/core/whatwg-fetch.js
+++ b/Libraries/vendor/core/whatwg-fetch.js
@@ -516,6 +516,10 @@
         xhr.withCredentials = false;
       }
 
+      if ('responseType' in xhr && support.blob) {
+        xhr.responseType = 'blob'
+      }
+
       request.headers.forEach(function(value, name) {
         xhr.setRequestHeader(name, value);
       });