diff --git a/src/util/minimal.js b/src/util/minimal.js
index 064b6dd3d..7f6df5eba 100644
--- a/src/util/minimal.js
+++ b/src/util/minimal.js
@@ -34,7 +34,7 @@ util.isNode = typeof global !== "undefined"
            && global
            && global.process
            && global.process.versions
-           && global.process.versions.node;
+           && typeof global.process.versions.node === "string";
 
 /**
  * Global object reference.