ES6 composition: mixins / traits using anonymous subclass factories

traits-mixins-example-class-composition.js

class Fig { constructor() { console.log("I'm Ficus carica") } }

const Dateable = (SC) => class extends SC { constructor() { super(); this.creationDate = new Date() } }
const Invisible = (SC) => class extends SC { isVisible() { return false } }

class InvisibleDateableFig extends Invisible(Dateable(Fig)) {}

let f = new  InvisibleDateableFig()

// > f
// InvisibleDateableFig { creationDate: 2017-01-26T04:28:32.313Z }
// > f instanceof Fig
// true
// > f.isVisible()
// false