1 files changed, 7 insertions, 7 deletions

diff --git a/lib/dns.js b/lib/dns.js
index 8cfa7f58c5..e084fb5e5d 100644
--- a/lib/dns.js
+++ b/lib/dns.js
@@ -53,7 +53,7 @@ function errnoException(err, syscall, hostname) {
 //   callback.immediately = true;
 // }
 function makeAsync(callback) {
-  if (!util.isFunction(callback)) {
+  if (typeof callback !== 'function') {
     return callback;
   }
   return function asyncCallback() {
@@ -96,7 +96,7 @@ exports.lookup = function lookup(hostname, options, callback) {
     family = 0;
   } else if (typeof callback !== 'function') {
     throw TypeError('invalid arguments: callback must be passed');
-  } else if (util.isObject(options)) {
+  } else if (options !== null && typeof options === 'object') {
     hints = options.hints >>> 0;
     family = options.family >>> 0;
 
@@ -192,9 +192,9 @@ function resolver(bindingName) {
   var binding = cares[bindingName];
 
   return function query(name, callback) {
-    if (!util.isString(name)) {
+    if (typeof name !== 'string') {
       throw new Error('Name must be a string');
-    } else if (!util.isFunction(callback)) {
+    } else if (typeof callback !== 'function') {
       throw new Error('Callback must be a function');
     }
 
@@ -228,17 +228,17 @@ exports.reverse = resolveMap.PTR = resolver('getHostByAddr');
 
 exports.resolve = function(hostname, type_, callback_) {
   var resolver, callback;
-  if (util.isString(type_)) {
+  if (typeof type_ === 'string') {
     resolver = resolveMap[type_];
     callback = callback_;
-  } else if (util.isFunction(type_)) {
+  } else if (typeof type_ === 'function') {
     resolver = exports.resolve4;
     callback = type_;
   } else {
     throw new Error('Type must be a string');
   }
 
-  if (util.isFunction(resolver)) {
+  if (typeof resolver === 'function') {
     return resolver(hostname, callback);
   } else {
     throw new Error('Unknown type "' + type_ + '"');