Javascript Const

Javascript const

Created By: chatGPT

const is a keyword in JavaScript used to declare a variable that cannot be reassigned. This means that once a variable is created with const, you cannot change its reference to another object or value. However, if it's an object or an array, you can still modify its contents.

const myConstant = 10;

myConstant = 20; // This will throw an error

You can create a const array or object, and while you can't reassign the variable itself, you can update the contents.

const myArray = [1, 2, 3];
myArray.push(4); // Allowed, modifies the contents

const myObject = { key: 'value' };
myObject.key = 'new value'; // Allowed, modifies the property

Scope is another important aspect of const. The variable declared with const is block-scoped, which means it exists only within the block where it is defined.

if (true) {
    const blockScopedVar = 'I am inside a block';
}

console.log(blockScopedVar); // This will throw an error

To summarize, const is used to create variables that should not be reassigned, and it works well with arrays and objects for manipulation of their contents. It is always a good practice to use const for variables that you do not plan to change.

const url = 'https://myapi.com'; // Good practice

// Example of error:
const myList = [];
myList = [1, 2, 3]; // Error