Value vs Reference

There are different data types are passed either by their value or by their reference.

Pass by Value

In JavaScript, primitive data types are passed by copy of their value. These primitive types are Number, String, Boolean, Null and Undefined.

Pass by Reference

A variable is assigned a non-primitive value such as Object, Array, Function, etc. it is given a reference to that objects location in memory.

Clonning Array

One Level Deep

// Shallow cloning - One level Deep

const original = [1, 2, 3, 4];

const newOg = [...original];

newOg.push(5);

console.log(original === newOg); //false

Two Level Deep

// Deep cloning - Two level Deep

const users = [
  { name: "John", age: 24 },

  { name: "Tom", age: 22 },
];

const newUser = JSON.parse(JSON.stringify(users));

console.log(users === newUser); //false