Singleton class I use for AS3 projects.

Singleton.as

// https://gist.github.com/mhulse/dbc517203ceddda2f675
package com.ieqtech {
	
	import flash.display.*;
	import flash.events.*;
	
	// http://stackoverflow.com/a/13318889/922323
	public final class Singleton extends MovieClip {
		
		private static var _instance:Singleton;
		
		public function Singleton() {
			
			if (_instance) {
				
				throw new Error('`Singleton()` already instantiated! Use `Singleton.getInstance()` instead.');
				
			}
			
			_instance = this;
			
			this.init();
			
		}
		
		public static function getInstance():Singleton {
			
			if ( ! _instance) {
				
				new Singleton();
				
			}
			
			return _instance;
			
		}
		
		private function init():void {
			
			(this.stage) ? main() : this.addEventListener(Event.ADDED_TO_STAGE, main, false, 0, true);
			
		}
		
		private function main($event:Event = null):void {
			
			if ($event !== null) {
				
				this.removeEventListener(Event.ADDED_TO_STAGE, init);
				
			}
			
			trace('Hello world!');
			
		}
		
	}
	
}