Prototype methods, objects without proto

The __proto__ is considered outdated and somewhat deprecated (in browser-only part of the JavaScript standard).
The modern methods are:

Object.create(proto, descriptors) – creates an empty object
Object.getPrototypeOf(obj) – returns the Prototype of obj.
Object.setPrototypeOf(obj, proto) – sets the Prototype of obj to proto.

let animal = {
  eats: true
};

// create a new object with animal as a prototype
let rabbit = Object.create(animal);

alert(rabbit.eats); // true

alert(Object.getPrototypeOf(rabbit) === animal); // true

Object.setPrototypeOf(rabbit, {}); // change the prototype of rabbit to {}
function Rabbit(name) {
  this.name = name;
}
Rabbit.prototype.sayHi = function() {
  alert(this.name);
};

let rabbit = new Rabbit("Rabbit")

rabbit.sayHi(); // "Rabbit"
Rabbit.prototype.sayHi(); //undefined
Object.getPrototypeOf(rabbit).sayHi(); //undefined
rabbit.__proto__.sayHi(); //undefined