What are JavaScript objects and prototypes?

JavaScript is a prototype-based language where objects can inherit directly from other objects.

Creating Objects:

// Object literal
const obj = { name: "John", age: 30 };
// Constructor function
function Person(name) {
  this.name = name;
}
const person = new Person("John");
// Object.create()
const obj = Object.create(prototype);

Prototype:
Every function has a prototype property, and every object has a __proto__ property.

function Person(name) {
  this.name = name;
}
Person.prototype.greet = function() {
  return "Hello, " + this.name;
};
const john = new Person("John");
console.log(john.greet()); // "Hello, John"

Prototype Chain:
When accessing a property, JavaScript looks:
1. On the object itself
2. On the object's prototype
3. Up the prototype chain until Object.prototype
4. Returns undefined if not found