diff --git a/index.js b/index.js
index 8cfd956..6ba7342 100644
--- a/index.js
+++ b/index.js
@@ -10,8 +10,6 @@
 var is = require('assertit').is;
 var matcher = require('is-match');
 var npmPkgs = require('npm-pkgs');
-// var fnName = require('fn-name');
-// var handle = require('handle-arguments');
 
 /**
  * Filter packages of the given [npmjs.com](http://npm.im) user,
@@ -44,9 +42,8 @@ module.exports = function npmPkgsFilter(username, patterns, callback) {
     if (!is.kindof.function(callback)) {
       throw new TypeError('[npm-pkgs-filter] expect `callback` to be function')
     }
-
     npmPkgs(username, function __npmPkgsFilterCallback(err, res) {
-      if (err) {
+      if (!is.kindof.null(err)) {
         callback(err);
         return;
       }
diff --git a/test.js b/test.js
index dcb426f..44086f2 100644
--- a/test.js
+++ b/test.js
@@ -93,4 +93,14 @@ test('npm-pkgs-filter:', function() {
       done();
     });
   });
+  test('should error when non existing user and filter patterns given', function(done) {
+    npmPkgsFilter('fjk43hkjhhhhhhhhhhhhhhhkjgg3k4g234', ['*js*', 'npm-*'], function _cb(err, res) {
+      test.is.error(err);
+      test.is.number(err.code);
+      test.is.undefined(res);
+      test.equal(err instanceof Error, true);
+      test.equal(err.code, 404);
+      done();
+    });
+  });
 });