Prototype error handling modal

src/app.js

@@ -5,20 +5,50 @@ import {Database} from './database.js';
 import React from 'react';
 import ReactDOM from 'react-dom';
 import {Mediator} from 'mediator-js';
+import Modal from 'react-modal';
 import Codemirror from 'react-codemirror';
 
 
 class App extends React.Component {
     constructor() {
         super();
         this.db = new Database();
+        this.closeErrorModal = this.closeErrorModal.bind(this);
+        this.state = {
+            errorMessage: '',
+            showError: false
+        };
+    }
+
+    componentDidMount() {
+        var self = this;
+        window.onerror = function(message, source, lineno, colno, error) {
+		    self.setState({
+                errorMessage: message,
+                showErrorModal: true
+            });
+        }
+    }
+
+    closeErrorModal() {
+        this.setState({
+            showErrorModal: false
+        });
     }
 
 	render() {
 		return <div className="app">
 			<Toolbar db={this.db} />
 			<Map />
 			<Editor db={this.db} />
+			<Modal
+			  isOpen={this.state.showErrorModal}
+			  className="dark-modal"
+			  overlayClassName="dark-overlay"
+			>
+			  <p>{this.state.errorMessage}</p>
+              <button onClick={this.closeErrorModal}>Close Modal...</button>
+			</Modal>
 		</div>;
 	}
 }