diff --git a/addons/knobs/src/components/PropForm.js b/addons/knobs/src/components/PropForm.js
index 5cdb4312bc9f..a477f502fbf8 100644
--- a/addons/knobs/src/components/PropForm.js
+++ b/addons/knobs/src/components/PropForm.js
@@ -10,7 +10,7 @@ export default class PropForm extends Component {
   makeChangeHandler(name, type) {
     const { onFieldChange } = this.props;
     return value => {
-      const change = { name, type, value };
+      const change = { name, type, value: value || '' };
 
       onFieldChange(change);
     };