javascript-pour-les-jedis-episode-3-snippet-10.js

function Force() {}
Jedi.prototype.toString = function () {
 return 'I am the Force';
};

function Jedi() {}
Jedi.prototype = Force.prototype;
Jedi.prototype.toString = function () {
 return 'I am a Jedi';
};

const luke = new Jedi();
const force = new Force();
console.log(luke instanceof Jedi); //=> true
console.log(luke instanceof Force); //=> true
console.log(luke + ''); //=> 'I am a Jedi'
console.log(force + ''); //=> 'I am a Jedi' <=== OH OH !!!!