TypeScript singleon pattern

singleton.ts

/**
 * Simple singleton pattern in TypeScript
 */
module Utils {

	class GreeterSingleton {	
    
		public sayHello(name:string) : void {
			alert(`Hello ${name}!`);
		}
	}
	
	export var Greeter = new GreeterSingleton();
}

Utils.Greeter.sayHello('World');


//////////////////////////////////////////////////////

module Module_As_Singleton {
	
	var prop1 = 'prop1'

	export function test1() {
		console.log(this.prop1 = 'prop1 original');
	}
	
	export function test2() {
		console.log(this.prop1 = 'prop1 changed');
	}
	
}

Module_As_Singleton.test2();