[JavaScript] Object-Oriented Programming (OOP) with JavaScript : Prototypal Inheritance on Built-in Objects (feat. prototype chain)

console.log(jonas.__proto__); // prototype of jonas

console.log(jonas.__proto__.__proto__); // top of the prototype chain
console.log(jonas.__proto__.__proto__.__proto__); // null

console.dir(Person.prototype.constructor);

const arr = [3, 6, 4, 5, 6, 9, 3]; // new Array === []
console.log(arr.__proto__);
console.log(arr.__proto__ === Array.prototype);

console.log(arr.__proto__.__proto__);

Array.prototype.unique = function () {
  return [...new Set(this)];
};

console.log(arr.unique());

• This is not a good way to add a prototype method. Because 1. JavaScript could update the method with the same name, then the bug can occur. 2. other developers in the team can use the same name, then it also can make some bugs.

// check prototype chains and inheritance
const h1 = document.querySelector('h1');
console.dir(x => x + 1);

• It is a huge prototype chain.