Prototype Chain & Inheritance

Every object has an internal [[Prototype]] (accessible via Object.getPrototypeOf).

const animal = { eats:true };
const rabbit = Object.create(animal);
rabbit.jumps = true;
console.log(rabbit.eats); // true – found on prototype

Prototype methods – Object.prototype.toString, Array.prototype.map.

Example: Adding a method to all objects

Object.prototype.log = function(){ console.log(this); };
({a:1}).log(); // {a:1}

(Use with caution – augmenting native prototypes can break libraries.)