const Availability = (Super = Object) => class extends Super {
    constructor() {
        super();
        this._isOpen = false;
    }
    open() {
        this._isOpen = true;
        return this;
    }
    close() {
        this._isOpen = false;
        return this;
    }
    isOpen() {
        return this._isOpen;
    }
};

const Membership = (Super = Object) => class extends Super {
    constructor() {
        super();
        this._members = {};
    }
    add(member) {
        this._members[member.name] = member;
        return this;
    }
    getMember(name) {
        return this._members[name];
    }
};

const Defaults = (Super = Object) => class extends Super {
    constructor(name = "The Saloon", specials = "Whisky, Gin, Tequila") {
        super();
        this._name = name;
        this._specials = specials;
    }
};

// This is multiple inheritance, **NOT** composition
class Bar extends Defaults(Availability(Membership())) {}

const myBar = new Bar("Moe's");

myBar.add({"name": "Homer"}).open().getMember("Homer")