diff --git a/src/utils/Disposables.js b/src/utils/Disposables.js
index e1d6b0a5..bd84ccf0 100644
--- a/src/utils/Disposables.js
+++ b/src/utils/Disposables.js
@@ -1,5 +1,5 @@
 function disposeValue(value) {
-    if (typeof d === "function") {
+    if (typeof value === "function") {
         value();
     } else {
         value.dispose();