diff --git a/lib/portal.js b/lib/portal.js
index 4bfb9ef..4d6ed84 100644
--- a/lib/portal.js
+++ b/lib/portal.js
@@ -117,7 +117,7 @@ export default class Portal extends React.Component {
       }
       this.portal = null;
       this.node = null;
-      if (!isUnmounted) {
+      if (isUnmounted !== true) {
         this.setState({active: false});
       }
     };