Will a const declaration protect your data from mutation? Well...not really!

Let's say I have an array with the following elements 7,2,5 and I have a function named "mutate"

const numbers = [7,2,5,]

function mutate (){ numbers.sort() console.log(numbers) }

console.log("numbers before function is called " +numbers)

//refactor function code above using arrow function

const mutate = () => numbers.sort()

//call function mutate()

console.log("numbers after function is called " +numbers)

if I call the variable "numbers" after the function you will notice that the result is [2,5,7].

A const declaration alone doesn't really protect your data from mutation. To ensure your data doesn't change, JavaScript provides a function Object.freeze to prevent data mutation.

let movies = { name:"Dune", review: "Awesome" };

Object.freeze(movies); //note : make sure to use uppercase "O" in Object.freeze()

movies.review = "bad"; movies.newProp = "Release_year"; console.log(movies);

If you attempt to change the movie's object, it will be rejected n