Add further explanation of ownProps in mstp (#26455)

* Add further explanation of ownProps in mstp

* Added syntax highlighting

guide/english/redux/tutorial/index.md

@@ -145,6 +145,15 @@ The example above demonstrates how the base App component is setup and how it wi
 
 Also how to dispatch a defined action from the component which will be passed down to the store and make the changes on the application reducer.
 
+`mapStateToProps` takes a second argument, `ownProps`, which are the props of the component. This can be useful for mapping props from the store based on the component's exisiting props. For example
+```javascript
+const mapStateToProps = (state, ownProps) => {
+    if (ownProps.userId) {
+        return { friends: state.friends[ownProps.userId }
+    }
+}
+```
+
 ## Declaration of the Application Actions
 
 The following file: