JavaScript(JS) const

const is a keyword in JavaScript introduced in ES6 (ECMAScript 2015) that is used to declare a constant variable that cannot be reassigned.

Declaring a variable with const creates a read-only reference to a value that cannot be changed. This means that once a variable is assigned a value using const, it cannot be reassigned to a different value.

Here's an example of using const to declare a constant variable:

const PI = 3.14159;

In this example, PI is declared as a constant variable and assigned the value of 3.14159. Once PI is assigned a value using const, it cannot be reassigned to a different value.

While const variables cannot be reassigned, their contents can still be modified if they are objects or arrays. For example, you can modify the contents of an array or object that is assigned to a const variable, but you cannot reassign the variable to a different array or object.

Using const can help prevent errors caused by accidental reassignment of variables and make it easier to reason about the code by clearly defining the values that should not be changed.