fix: support legacy blob implementations

Author: TalLevAmi

lib/uploader.js

@@ -107,6 +107,11 @@ function getBlobArrayBuffer(file) {
     return file.arrayBuffer();
   }
 
+  let blobBuffer = getBlobBuffer(file);
+  if (blobBuffer) {
+    return Promise.resolve(blobBuffer.buffer.slice(blobBuffer.byteOffset, blobBuffer.byteOffset + blobBuffer.byteLength));
+  }
+
   if (typeof FileReader !== "undefined") {
     return new Promise((resolve, reject) => {
       let reader = new FileReader();
@@ -123,6 +128,21 @@ function getBlobArrayBuffer(file) {
   return Promise.reject(new Error("Blob upload requires Blob.arrayBuffer() or FileReader support"));
 }
 
+function getBlobBuffer(file) {
+  if (typeof Object.getOwnPropertySymbols !== "function") {
+    return null;
+  }
+
+  for (let symbol of Object.getOwnPropertySymbols(file)) {
+    let implementation = file[symbol];
+    if (implementation && Buffer.isBuffer(implementation._buffer)) {
+      return implementation._buffer;
+    }
+  }
+
+  return null;
+}
+
 function isUploadData(file) {
   return Buffer.isBuffer(file) || isUint8Array(file) || isArrayBuffer(file);
 }