Convert from React.createClass to ES6 classes

Reviewed By: cpojer

Differential Revision: D3619143

fbshipit-source-id: e14e81468d467437ee3d79c34c34b7780a46ca1c

Examples/UIExplorer/js/AppStateExample.js

@@ -31,33 +31,36 @@ const {
   View
 } = ReactNative;
 
-var AppStateSubscription = React.createClass({
-  getInitialState() {
-    return {
-      appState: AppState.currentState,
-      previousAppStates: [],
-      memoryWarnings: 0,
-    };
-  },
-  componentDidMount: function() {
+class AppStateSubscription extends React.Component {
+  state = {
+    appState: AppState.currentState,
+    previousAppStates: [],
+    memoryWarnings: 0,
+  };
+
+  componentDidMount() {
     AppState.addEventListener('change', this._handleAppStateChange);
     AppState.addEventListener('memoryWarning', this._handleMemoryWarning);
-  },
-  componentWillUnmount: function() {
+  }
+
+  componentWillUnmount() {
     AppState.removeEventListener('change', this._handleAppStateChange);
     AppState.removeEventListener('memoryWarning', this._handleMemoryWarning);
-  },
-  _handleMemoryWarning: function() {
+  }
+
+  _handleMemoryWarning = () => {
     this.setState({memoryWarnings: this.state.memoryWarnings + 1});
-  },
-  _handleAppStateChange: function(appState) {
+  };
+
+  _handleAppStateChange = (appState) => {
     var previousAppStates = this.state.previousAppStates.slice();
     previousAppStates.push(this.state.appState);
     this.setState({
       appState,
       previousAppStates,
     });
-  },
+  };
+
   render() {
     if (this.props.showMemoryWarnings) {
       return (
@@ -79,7 +82,7 @@ var AppStateSubscription = React.createClass({
       </View>
     );
   }
-});
+}
 
 exports.title = 'AppState';
 exports.description = 'app background status';