Example of Mixin composition and inheritance in ES6

MixinsCompositionAndInheritance.js

function printPrototypeChain(obj){
	let protoNames = [];
	let curProto = Object.getPrototypeOf(obj);
	while (curProto){
		protoNames.push(curProto.constructor.name);
		curProto = Object.getPrototypeOf(curProto);
	}
	console.log("prototype chain:\n" + protoNames.join("."));
}

class MySuperClass{

}

let Mixin1 = (superclass) => class Mixin1GeneratedSubclass extends(superclass){
	method1(){
		console.log("method1");
	}
};

let Mixin2 = (superclass) => class Mixin2GeneratedSubclass extends(superclass){
	method2(){
		console.log("method2");
	}
};

function mixinInheritanceTest(){
	//Mixin Inheritance. Here I create a new class factory function (Mixin3). It applies other 2 existing mixins to the provided subclass and <strong>adds new methods</strong> to it. For that it's indeed creating an additional class in the prototype chain: ClassA -> Mixin3GeneratedSubclass -> Mixin2GeneratedSubClass -> Mixin1GeneratedSubclass -> superclass</p>
	let Mixin3 = (superclass) => class Mixin3GeneratedSubclass extends Mixin2(Mixin1(superclass)){
		method3(){
			console.log("method3");
		}
	};

	class ClassA extends Mixin3(MySuperClass){
		methodClassA(){
			console.log("methodClassA");
		}
	}

	let a1 = new ClassA();

	printPrototypeChain(a1);
}

function mixinCompositionTest(){
	//Mixin Composition. Here I create a new class factory function by combining 2 existing mixins, but it's <strong>not adding new methods</strong> of its own. That's the difference with the previous case, it does not need to add one more class. When used we'll get: ClassA -> Mixin2GeneratedSubClass -> Mixin1GeneratedSubclass -> superclass.</p>
	let Mixin3 = (superclass) => Mixin2(Mixin1(superclass));
		
	class ClassA extends Mixin3(MySuperClass){
		methodClassA(){
			console.log("methodClassA");
		}
	}

	let a1 = new ClassA();

	printPrototypeChain(a1);
}

console.log("- Mixin Inheritance");
mixinInheritanceTest();

console.log("------------------");

console.log("- Mixin Composition");
mixinCompositionTest();