merge from master

1 files changed, 3 insertions, 2 deletions

diff --git a/lib/memoize.js b/lib/memoize.js
index 59c8ae3..963e031 100644
--- a/lib/memoize.js
+++ b/lib/memoize.js
@@ -2,6 +2,7 @@
 
 import identity from 'lodash/identity';
 import rest from 'lodash/rest';
+import has from 'lodash/has';
 
 import setImmediate from './internal/setImmediate';
 
@@ -12,11 +13,11 @@ export default function memoize(fn, hasher) {
     var memoized = rest(function memoized(args) {
         var callback = args.pop();
         var key = hasher.apply(null, args);
-        if (key in memo) {
+        if (has(memo, key)) {
             setImmediate(function() {
                 callback.apply(null, memo[key]);
             });
-        } else if (key in queues) {
+        } else if (has(queues, key)) {
             queues[key].push(callback);
         } else {
             queues[key] = [callback];