add base class for auto-binding this (es6).

src/js/auto-binding-object.js

@@ -0,0 +1,73 @@
+/*
+ * auto-binding-object.js
+ *
+ * Copyright © 2016 Antergos Developers <dev@antergos.com>
+ *
+ * This file is part of lightdm-webkit2-greeter.
+ *
+ * lightdm-webkit2-greeter is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * lightdm-webkit2-greeter is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * The following additional terms are in effect as per Section 7 of the license:
+ *
+ * The preservation of all legal notices and author attributions in
+ * the material or in the Appropriate Legal Notices displayed
+ * by works containing it is required.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with lightdm-webkit2-greeter; If not, see <http://www.gnu.org/licenses/>.
+ */
+
+
+/**
+ * Generic base class that automatically binds `this` to the instance for all class methods.
+ * It is made available in the global scope and can be used in greeter themes if needed/wanted.
+ */
+class AutoBindingObject {
+	/**
+	 * Creates a new {@link AutoBindingObject} instance.
+	 */
+	constructor() {
+		this.__bind_this();
+	}
+
+	/**
+	 * Binds `this` to the class for all class methods.
+	 *
+	 * @private
+	 */
+	__bind_this() {
+		let excluded_methods = ['constructor', '__bind_this'];
+
+		function not_excluded( method, context ) {
+			let _is_excluded = excluded_methods.findIndex( excluded_method => method === excluded_method ) > -1,
+				is_method = 'function' === typeof context[method];
+
+			return is_method && !_is_excluded;
+		}
+
+		for ( let obj = this; obj; obj = Object.getPrototypeOf( obj ) ) {
+			// Handle only our methods
+			if ( 'Object' === obj.constructor.name ) {
+				break;
+			}
+
+			for ( let method of Object.getOwnPropertyNames( obj ) ) {
+				if ( not_excluded( method, this ) ) {
+					this[method] = this[method].bind( this );
+				}
+			}
+		}
+
+	}
+}
+
+
+window.AutoBindingObject = AutoBindingObject;

src/js/heartbeat.js

@@ -37,22 +37,23 @@
  * subsequent checks run, it will assume that there has been an error in the theme's script
  * execution and fall back to the simple theme.
  */
-class LightDMGreeterHeartbeat {
+class LightDMGreeterHeartbeat extends AutoBindingObject {
 
 	constructor() {
-		if ( '_heartbeat' in window ) {
-			return _heartbeat;
+		if ( '__heartbeat' in window ) {
+			return __heartbeat;
 		}
 
-		window._heartbeat = this;
+		super();
+
+		window.__heartbeat = this;
 		this.heartbeat = '';
+		this.heartbeats = 0;
 
 		this.initialize_theme_heartbeat();
 	}
 
 	initialize_theme_heartbeat() {
-		let heartbeats = 0;
-
 		if ( '' !== this.heartbeat ) {
 			console.log( 'Heartbeat has already been initialized!' );
 			return;
@@ -60,21 +61,23 @@ class LightDMGreeterHeartbeat {
 
 		console.log('Initializing theme heartbeat.');
 
-		this.heartbeat = setInterval(() => {
-			++heartbeats;
+		this.send_heartbeat();
+		this.heartbeat = setInterval(this.send_heartbeat, 5000);
+	}
 
-			if ( true === lightdm.session_starting ) {
-				clearInterval( this.heartbeat );
-				return;
-			}
+	send_heartbeat() {
+		++this.heartbeats;
 
-			window.webkit.messageHandlers.GreeterBridge.postMessage('Heartbeat');
+		if ( true === lightdm.session_starting ) {
+			clearInterval( this.heartbeat );
+			return;
+		}
 
-			if ( heartbeats < 5 ) {
-				console.log('Sending heartbeat...');
-			}
+		if ( this.heartbeats < 5 ) {
+			console.log('Sending heartbeat...');
+		}
 
-		}, 5000);
+		window.webkit.messageHandlers.GreeterBridge.postMessage('Heartbeat');
 	}
 }