From 35d785e7011c0304ae9dd5de1d7112f285c2056b Mon Sep 17 00:00:00 2001
From: faupol3 <45740133+faupol3@users.noreply.github.com>
Date: Fri, 5 Nov 2021 19:04:10 -0300
Subject: [PATCH] Update isImage helper with file signatures

---
 src/helpers.js | 25 +++++++++++++++++++++++--
 1 file changed, 23 insertions(+), 2 deletions(-)

diff --git a/src/helpers.js b/src/helpers.js
index b9b6398c..1fc3d108 100644
--- a/src/helpers.js
+++ b/src/helpers.js
@@ -1,7 +1,28 @@
 export function isImage(file) {
-    if (file.type.split('/')[0] === 'image') {
-        return true;
+    var reader = new FileReader();
+    reader.onloadend = (event) => {
+        var arr = (new Uint8Array(event.target.result)).subarray(0, 4);
+        var header = "";
+        for (var i = 0; i < arr.length; i++) {
+            header += arr[i].toString(16);
+        }
+
+        switch (header) {
+            case "47494638": // GIF
+            case "52494646": // WEBP
+            case "89504e47": // PNG
+            case "ffd8ffe0": // JPEG
+            case "ffd8ffe1": // JPEG
+            case "ffd8ffe2": // JPEG
+            case "ffd8ffe3": // JPEG
+            case "ffd8ffe8": // JPEG
+                return true;
+            default:
+                return false;
+        }
+
     }
+    fileReader.readAsArrayBuffer(file);
 }
 
 export function convertBytesToMbsOrKbs(filesize) {