diff --git a/lib/utils/action-logger.js b/lib/utils/action-logger.js
--- a/lib/utils/action-logger.js
+++ b/lib/utils/action-logger.js
@@ -137,8 +137,10 @@
     return this.lastNActions[this.lastNActions.length - 1].time;
   }
 
-  get currentState(): Object {
-    const state = this.currentReduxState ? { ...this.currentReduxState } : {};
+  get currentState(): { +[string]: mixed } {
+    const state: { [string]: mixed } = this.currentReduxState
+      ? { ...this.currentReduxState }
+      : {};
     for (const stateKey in this.currentOtherStates) {
       state[stateKey] = this.currentOtherStates[stateKey];
     }