diff --git a/lib/freeze.js b/lib/freeze.js
index e4d8eb4..cd1ae6a 100644
--- a/lib/freeze.js
+++ b/lib/freeze.js
@@ -1,9 +1,10 @@
 function isFreezable(obj) {
-  if (Object.isFrozen(obj)) {
-    return false;
-  }
+  return Array.isArray(obj) ||
+    typeof obj === 'object';
+}
 
-  return Array.isArray(obj) || typeof obj === 'object';
+function needsFreezing(obj) {
+  return isFreezable(obj) && !Object.isFrozen(obj);
 }
 
 function recur(obj) {
@@ -11,7 +12,7 @@ function recur(obj) {
 
   Object.keys(obj).forEach((key) => {
     const value = obj[key];
-    if (isFreezable(value)) {
+    if (needsFreezing(value)) {
       recur(value);
     }
   });
@@ -24,7 +25,7 @@ export default function freeze(obj) {
     return obj;
   }
 
-  if (isFreezable(obj)) {
+  if (needsFreezing(obj)) {
     recur(obj);
   }