From 59a60acf0973f2d378e458816e063eb4ba2787cd Mon Sep 17 00:00:00 2001
From: Kyle Corbitt <kyle@corbt.com>
Date: Mon, 3 Oct 2016 17:28:15 -0700
Subject: [PATCH] check if callbacks are functions

---
 FS.common.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/FS.common.js b/FS.common.js
index 79b544b..b01108a 100644
--- a/FS.common.js
+++ b/FS.common.js
@@ -332,7 +332,7 @@ var RNFS = {
     if (options.begin) {
       subscriptions.push(NativeAppEventEmitter.addListener('UploadBegin-' + jobId, options.begin));
     }
-    if (options.beginCallback) {
+    if (options.beginCallback && options.beginCallback instanceof Function) {
       // Deprecated
       subscriptions.push(NativeAppEventEmitter.addListener('UploadBegin-' + jobId, options.beginCallback));
     }
@@ -340,7 +340,7 @@ var RNFS = {
     if (options.progress) {
       subscriptions.push(NativeAppEventEmitter.addListener('UploadProgress-' + jobId, options.progress));
     }
-    if (options.progressCallback) {
+    if (options.progressCallback && options.progressCallback instanceof Function) {
       // Deprecated
       subscriptions.push(NativeAppEventEmitter.addListener('UploadProgress-' + jobId, options.progressCallback));
     }