diff --git a/src/tabs/getItemString.js b/src/tabs/getItemString.js
index 04ebbbd..1117e83 100644
--- a/src/tabs/getItemString.js
+++ b/src/tabs/getItemString.js
@@ -5,12 +5,13 @@ import getType from '../utils/getType';
 import type { StylingFunction } from 'react-base16-styling';
 
 function getShortTypeString(val: any, diff?: boolean): string {
-  const type = getType(val);
 
   if (diff && Array.isArray(val)) {
     val = val[val.length === 2 ? 1 : 0];
   }
 
+  const type = getType(val);
+
   switch (type) {
   case 'Immutable List':
   case 'Immutable Stack':
diff --git a/src/types.js b/src/types.js
index abf25fd..d986b09 100644
--- a/src/types.js
+++ b/src/types.js
@@ -1,3 +1,5 @@
+// @noflow
+
 export type Action = {
   timestamp: Date,
   error: ?string