diff --git a/packages/shared/ReactIODescription.js b/packages/shared/ReactIODescription.js
index 7fa6bb243936f..e1a0fce2c4d0a 100644
--- a/packages/shared/ReactIODescription.js
+++ b/packages/shared/ReactIODescription.js
@@ -7,7 +7,7 @@
  * @flow
  */
 
-export function getIODescription(value: any): string {
+export function getIODescription(value: mixed): string {
   if (!__DEV__) {
     return '';
   }
@@ -34,11 +34,13 @@ export function getIODescription(value: any): string {
           return value.command;
         } else if (
           typeof value.request === 'object' &&
+          value.request !== null &&
           typeof value.request.url === 'string'
         ) {
           return value.request.url;
         } else if (
           typeof value.response === 'object' &&
+          value.response !== null &&
           typeof value.response.url === 'string'
         ) {
           return value.response.url;
@@ -53,7 +55,11 @@ export function getIODescription(value: any): string {
           return value.name;
         } else {
           const str = value.toString();
-          if (str.startWith('[object ') || str.length < 5 || str.length > 500) {
+          if (
+            str.startsWith('[object ') ||
+            str.length < 5 ||
+            str.length > 500
+          ) {
             // This is probably not a useful description.
             return '';
           }