diff --git a/src/filesystem/implementation.js b/src/filesystem/implementation.js
index 3027688..90fbd22 100644
--- a/src/filesystem/implementation.js
+++ b/src/filesystem/implementation.js
@@ -1873,7 +1873,7 @@ function writeFile(context, path, data, options, callback) {
   if(typeof data === 'number') {
     data = '' + data;
   }
-  if(typeof data === 'string' && options.encoding === 'utf8') {
+  if(typeof data === 'string' && (options.encoding || 'utf8') === 'utf8') {
     data = Buffer.from(data);
   }