diff --git a/lib/fs.js b/lib/fs.js
index 99defef..b897ba4 100644
--- a/lib/fs.js
+++ b/lib/fs.js
@@ -240,13 +240,13 @@ function copyDir(src, dest, options = {}, callback) {
     options = {};
   }
 
-  return checkParent(dest).then() => _copyDir(src, dest, options, '').asCallback(callback);
+  return checkParent(dest).then(() => _copyDir(src, dest, options, '')).asCallback(callback);
 }
 
-function _listDir(path, options = {}, parent = '') {
+function _listDir(path, options, parent) {
   return _readAndFilterDir(path, options).map(item => {
     const currentPath = join(parent, item.path);
-    
+
     if (item.isDirectory) {
       return _listDir(item.fullPath, options, currentPath);
     }
@@ -269,11 +269,11 @@ function listDir(path, options = {}, callback) {
 function _listDirSync(path, options, parent) {
   return _readAndFilterDirSync(path, options).map(item => {
     const currentPath = join(parent, item.path);
-    
+
     if (item.isDirectory) {
       return _listDirSync(item.fullPath, options, currentPath);
     }
-    
+
     return currentPath;
   }).reduce(reduceFiles, []);
 }
@@ -296,7 +296,7 @@ function escapeFileContent(content) {
   return escapeBOM(escapeEOL(content));
 }
 
-function readFile(path, options =  {}, callback) {
+function readFile(path, options = {}, callback) {
   if (!path) throw new TypeError('path is required!');
 
   if (!callback && typeof options === 'function') {
@@ -304,7 +304,6 @@ function readFile(path, options =  {}, callback) {
     options = {};
   }
 
-  options = options || {};
   if (!options.hasOwnProperty('encoding')) options.encoding = 'utf8';
 
   return readFileAsync(path, options).then(content => {