constructorInheritance.js

function Factory() {
  this.foo = 1;
  this.bar = 'string';
}

Factory.prototype.example = "I'm a property of Factory.prototype";
console.log(Factory.prototype); // { example: "I'm a property of Factory.prototype" }

let descendant = new Factory();
console.log(descendant); // Factory { foo: 1, bar: 'string' }
console.log(descendant.example); // I'm a property of Factory.prototype