diff --git a/src/utils.js b/src/utils.js
index 4c25b31..9e61fa1 100644
--- a/src/utils.js
+++ b/src/utils.js
@@ -144,11 +144,7 @@ export function grayscale ({red, green, blue}) {
 }
 
 export function extend (obj, ...sources) {
-	return Object.assign({}, obj, ...sources);
-}
-
-export function extendDeep (obj, ...sources) {
-	let extended = extend(obj);
+	const extended = Object.assign({}, obj);
 
 	sources.forEach(src => {
 		forEach(src, (value, key) => {