Introduction and Lesson Objectives

Hello, future JavaScript star! Today, we're delving into the world of Lists and Arrays, in JavaScript. A list, much like a drawer, holds numerous values within a single container. By the end of this lesson, we will have mastered the essential tactics for efficiently crafting, accessing, and manipulating JavaScript lists.

Defining Lists: The Basics

Think of a list, or array, as a fleet of spaceships, where each ship carries a distinct item. So, you may ask, how does one assemble this space fleet? There are two methods:

  • Using the array constructor new Array():
  • Using brackets []:

Both techniques swiftly create a list, so feel free to choose the one you prefer!

Navigating with Indexing

Indexes in lists are akin to celestial coordinates. Each item in a list has an index that starts from 0 — this is specific to JavaScript.

The .indexOf() function assists us in locating "Mars" within the planets list.

List Properties: length Property

Determining list length is analogous to counting stars in a constellation. JavaScript achieves this with the .length property:

Easy and simple!

Assigning and Changing list Elements

Just like planets may change their positions in the universe, so can the elements inside a list. We can replace, add, or modify items inside our lists or arrays.

In the above example, we replaced "Venus", the second item in the list (at index 1), with "Cybertron". It's as simple as that!

What if we want to modify a value instead of completely replacing it? We can retrieve the item, make our modifications, and then put it back into the list.

In the above example, we updated the "Mars" element in the list, appending a string to it. The result is that "Mars" has been replaced with "Mars - the Red Planet".

Manipulating lists is a frequent operation in JavaScript. Thus, understanding how to assign and change array elements is essential for every JavaScript developer!

Basic List Operations: push() and pop()

To interact dynamically with our list, there are two main functions - push(element) and pop().

  • push(element) adds the element to the end of the list.
  • pop() removes the last element of the list and returns it as a result.

Let's show it on example - we will add "Pluto" using .push() and then remove it using .pop():

During this process, you've learned how to add and remove list elements using .push() and .pop(), respectively.

Wrapping up Adventure and Looking Forward

Congratulations! You've orbited the realm of JavaScript lists, learning how to create them, access elements by index, and perform basic operations. As we move forward, brace yourself for practice sessions that will reinforce your understanding of the concepts covered. Ready? Set. Code!

Sign up
Join the 1M+ learners on CodeSignal
Be a part of our community of 1M+ users who develop and demonstrate their skills on CodeSignal