diff --git a/lib/addClassNames.js b/lib/addClassNames.js
index a8007da..79605b3 100644
--- a/lib/addClassNames.js
+++ b/lib/addClassNames.js
@@ -4,11 +4,14 @@ const pseudoRegexp = require("./pseudoRegexp"),
 
     groups = require("./groups"),
 
-    uniq = require("lodash/uniq");
+    flatten = require("lodash/flatten"),
+    uniq    = require("lodash/uniq");
 
 
 module.exports = function addClassNames(classNames, include) {
-    include.forEach((inc) => {
+    include = typeof include === "string" ? [ include ] : include;
+
+    flatten(include).forEach((inc) => {
         if(pseudoRegexp.test(inc)) {
             return classNames.push(inc);
         }
diff --git a/lib/getClassNameFns.js b/lib/getClassNameFns.js
index c7bb8ef..7852d0c 100644
--- a/lib/getClassNameFns.js
+++ b/lib/getClassNameFns.js
@@ -3,27 +3,13 @@
 const classNameFunctions = require("./classNameFunctions"),
 
     addClassNames    = require("./addClassNames"),
-    removeClassNames = require("./removeClassNames"),
-
-    flatten = require("lodash/flatten");
-
-
-function shallowArray(item) {
-    if(!Array.isArray(item)) {
-        item = [ item ];
-    }
-
-    return flatten(item);
-}
+    removeClassNames = require("./removeClassNames");
 
 
 module.exports = function(config) {
     let classNames     = [],
         classFunctions = {};
 
-    config.include = shallowArray(config.include);
-    config.exclude = shallowArray(config.exclude);
-
     classNames = addClassNames(classNames, config.include);
     classNames = removeClassNames(classNames, config.exclude);
 
diff --git a/lib/removeClassNames.js b/lib/removeClassNames.js
index a57a7f2..6103dd3 100644
--- a/lib/removeClassNames.js
+++ b/lib/removeClassNames.js
@@ -4,11 +4,14 @@ const pseudoRegexp = require("./pseudoRegexp"),
 
     groups = require("./groups"),
 
-    pull = require("lodash/pull");
+    flatten = require("lodash/flatten"),
+    pull    = require("lodash/pull");
 
 
 module.exports = function(classNames, exclude) {
-    exclude.forEach((exc) => {
+    exclude = typeof exclude === "string" ? [ exclude ] : exclude;
+
+    flatten(exclude).forEach((exc) => {
         if(pseudoRegexp.test(exc)) {
             return pull(classNames, exc);
         }