From 93a669bd907cc60784ee95a31f7708ba566ed323 Mon Sep 17 00:00:00 2001
From: MuchtarSalimov <muchtarsalimov@gmail.com>
Date: Tue, 16 Oct 2018 14:01:46 -0400
Subject: [PATCH] Extended to check for more undefined parameters

---
 src/filesystem/implementation.js | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/src/filesystem/implementation.js b/src/filesystem/implementation.js
index e11be52..303e56d 100644
--- a/src/filesystem/implementation.js
+++ b/src/filesystem/implementation.js
@@ -1874,6 +1874,18 @@ function appendFile(fs, context, path, data, options, callback) {
   if (typeof options === 'object' && options.encoding === undefined ) {
     options.encoding = 'utf8';
   }
+  
+  if typeof (options ==== 'object') {
+    if (options.encoding === undefined) {
+      options.encoding = 'utf8';
+    }
+    if (options.mode === undefined) {
+      options.mode = 0o666;
+    }
+    if (options.flag === undefined) {
+      options.flag = 'a';
+    }
+  }
 
   data = data || '';
   if(typeof data === 'number') {