In today's lesson, we'll explore arrays in JavaScript, a versatile and fundamental data structure. An array is an ordered collection of elements that can be of mixed data types. Arrays in JavaScript are mutable, meaning their elements can be changed after creation. However, arrays can be made immutable using certain techniques if needed.

The beauty of arrays lies in their simplicity and efficiency; they allow for easy storage, access, and manipulation of data. By the end of this lesson, you'll be able to create, manipulate, and understand the unique applications of arrays in JavaScript.

An array in JavaScript is an ordered collection of elements, which can be of any type, including numbers, strings, objects, and even other arrays.

Consider this JavaScript array declaration as an example:

Arrays are created by enclosing elements in square brackets [], with commas to separate them — this is known as the array literal syntax. You can also create arrays using the Array constructor function. It is considered a best practice to declare arrays with const in JavaScript because const ensures that the variable holding the array reference cannot be reassigned to a different array or any other value. However, while the reference to the array is immutable, the contents of the array itself are still mutable (i.e., you can change the elements of the array).