handle json case and also handle both ArrayBuffer and Buffer passed by 'data' callback equally

Author: tchakabam

lib/index.js

@@ -316,7 +316,12 @@ NodeHttpXHR.prototype = Object.create(
         case 'text':
           return this._responseText;
         case 'arraybuffer':
-          return this._response;
+        case 'json':
+          if (this._response instanceof ArrayBuffer) {
+            return this._response;
+          } else if (this._response instanceof Buffer) {
+            return this._response.buffer;
+          }
         default:
           throw new Error('Assertion failed: unsupported response-type: ' + type);
         }