alert is in the Alert module (facebook#423)

hoyajigi · charpeni · commit 8ee50156629a · 2018-06-27T12:00:57.000-04:00
I think this was a mistake
diff --git a/docs/modal.md b/docs/modal.md
@@ -9,7 +9,7 @@ The Modal component is a simple way to present content above an enclosing view.
 
 ```javascript
 import React, {Component} from 'react';
-import {Modal, Text, TouchableHighlight, View} from 'react-native';
+import {Modal, Text, TouchableHighlight, View, Alert} from 'react-native';
 
 class ModalExample extends Component {
   state = {
@@ -28,7 +28,7 @@ class ModalExample extends Component {
           transparent={false}
           visible={this.state.modalVisible}
           onRequestClose={() => {
-            alert('Modal has been closed.');
+            Alert.alert('Modal has been closed.');
           }}>
           <View style={{marginTop: 22}}>
             <View>
