diff --git a/dedupe.js b/dedupe.js
index 7d20bdf..f16329f 100644
--- a/dedupe.js
+++ b/dedupe.js
@@ -1,94 +1,85 @@
-const classNames = (function () {
-	// don't inherit from Object so we can skip hasOwnProperty check later
-	// http://stackoverflow.com/questions/15518328/creating-js-object-with-object-createnull#answer-21079232
-	function StorageObject() {}
-	StorageObject.prototype = Object.create(null);
-
-	function _parseArray (resultSet, array) {
-		const length = array.length;
-
-		for (let i = 0; i < length; ++i) {
-			_parse(resultSet, array[i]);
-		}
+// Don't inherit from Object so we can skip hasOwnProperty check later.
+function StorageObject () {}
+StorageObject.prototype = Object.create(null);
+
+export default function classNames () {
+	// Don't leak arguments.
+	// https://github.com/petkaantonov/bluebird/wiki/Optimization-killers#32-leaking-arguments
+	const length = arguments.length;
+	const args = Array(length);
+
+	for (let i = 0; i < length; i++) {
+		args[i] = arguments[i];
 	}
 
-	const hasOwn = {}.hasOwnProperty;
-
-	function _parseNumber (resultSet, num) {
-		resultSet[num] = true;
-	}
+	const classSet = new StorageObject();
+	appendArray(classSet, args);
 
-	function _parseObject (resultSet, object) {
-		if (object.toString !== Object.prototype.toString && !object.toString.toString().includes('[native code]')) {
-			resultSet[object.toString()] = true;
-			return;
-		}
+	const list = [];
 
-		for (const k in object) {
-			if (hasOwn.call(object, k)) {
-				// set value to false instead of deleting it to avoid changing object structure
-				// https://www.smashingmagazine.com/2012/11/writing-fast-memory-efficient-javascript/#de-referencing-misconceptions
-				resultSet[k] = !!object[k];
-			}
+	for (const k in classSet) {
+		if (classSet[k]) {
+			list.push(k);
 		}
 	}
 
-	const SPACE = /\s+/;
-	function _parseString (resultSet, str) {
-		const array = str.split(SPACE);
-		const length = array.length;
-
-		for (let i = 0; i < length; ++i) {
-			resultSet[array[i]] = true;
-		}
+	return list.join(' ');
+}
+
+function appendValue (classSet, arg) {
+	if (!arg) return;
+	const argType = typeof arg;
+
+	if (argType === 'string') {
+		appendString(classSet, arg);
+	} else if (Array.isArray(arg)) {
+		appendArray(classSet, arg);
+	} else if (argType === 'object') {
+		appendObject(classSet, arg);
+	} else if (argType === 'number') {
+		appendNumber(classSet, arg);
 	}
+}
 
-	function _parse (resultSet, arg) {
-		if (!arg) return;
-		const argType = typeof arg;
+const SPACE = /\s+/;
 
-		// 'foo bar'
-		if (argType === 'string') {
-			_parseString(resultSet, arg);
+function appendString (classSet, str) {
+	const array = str.split(SPACE);
+	const length = array.length;
 
-		// ['foo', 'bar', ...]
-		} else if (Array.isArray(arg)) {
-			_parseArray(resultSet, arg);
+	for (let i = 0; i < length; ++i) {
+		classSet[array[i]] = true;
+	}
+}
 
-		// { 'foo': true, ... }
-		} else if (argType === 'object') {
-			_parseObject(resultSet, arg);
+function appendArray (classSet, array) {
+	const length = array.length;
 
-		// '130'
-		} else if (argType === 'number') {
-			_parseNumber(resultSet, arg);
-		}
+	for (let i = 0; i < length; ++i) {
+		appendValue(classSet, array[i]);
 	}
+}
 
-	function _classNames () {
-		// don't leak arguments
-		// https://github.com/petkaantonov/bluebird/wiki/Optimization-killers#32-leaking-arguments
-		const length = arguments.length;
-		const args = Array(length);
-		for (let i = 0; i < length; i++) {
-			args[i] = arguments[i];
-		}
+function appendNumber (classSet, num) {
+	classSet[num] = true;
+}
 
-		const classSet = new StorageObject();
-		_parseArray(classSet, args);
+const hasOwn = {}.hasOwnProperty;
 
-		const list = [];
+function appendObject (classSet, object) {
+	if (
+		object.toString !== Object.prototype.toString &&
+		!object.toString.toString().includes('[native code]')
+	) {
+		classSet[object.toString()] = true;
+		return;
+	}
 
-		for (const k in classSet) {
-			if (classSet[k]) {
-				list.push(k)
-			}
+	for (const k in object) {
+		if (hasOwn.call(object, k)) {
+			// Set value to false instead of deleting it to avoid changing object structure.
+			// https://www.smashingmagazine.com/2012/11/writing-fast-memory-efficient-javascript/#de-referencing-misconceptions
+			classSet[k] = !!object[k];
 		}
-
-		return list.join(' ');
 	}
-
-	return _classNames;
-})();
-
-export default classNames;
+}