simplify handling of arraybuffer case and properly handle json data

Author: tchakabam

lib/index.js

@@ -1,7 +1,5 @@
 'use strict';
 
-/* global ArrayBuffer */
-
 /**
  * Node.js `XMLHttpRequest` implementation using `http.request()`.
  *
@@ -315,13 +313,10 @@ NodeHttpXHR.prototype = Object.create(
         case '':
         case 'text':
           return this._responseText;
-        case 'arraybuffer':
         case 'json':
-          if (this._response instanceof ArrayBuffer) {
-            return this._response;
-          } else if (this._response instanceof Buffer) {
-            return this._response.buffer;
-          }
+          return JSON.parse(this._responseText);
+        case 'arraybuffer':
+          return this._response.buffer;
         default:
           throw new Error('Assertion failed: unsupported response-type: ' + type);
         }
@@ -518,18 +513,12 @@ NodeHttpXHR.prototype.send = function (data) {
       if (typeof chunk === 'string') {
         this._responseText += chunk;
       } else if (typeof chunk === 'object') {
-        if (chunk instanceof Buffer) {
-          if (this._response) {
-            this._response = Buffer.concat([this._response, chunk]);
-          } else {
-            this._response = chunk;
-          }
-        // binary data usually comes in one chunk (no chunky transfer-encoding)
-        // or at least, that's what we'll support here for now for ArrayBuffer
-        } else if (chunk instanceof ArrayBuffer) {
-          this._response = chunk;
+        if (!(chunk instanceof Buffer)) {
+          throw new Error('Assertion failed: Response-data should be of `Buffer` type');
+        }
+        if (this._response) {
+          this._response = Buffer.concat([this._response, chunk]);
         } else {
-          // JSON case
           this._response = chunk;
         }
       }