Fundamentals: Part 5 (v1)


Objects are a very important part of the JavaScript language, and while for the most part you can accomplish simple and even intermediate tasks without worrying about them, any real project that you’re going to attempt is going to feature Objects. The uses of Objects in JavaScript can get deep relatively quickly, so for the moment we’re only going to cover the basics. There’ll be an in-depth dive later.

  1. This article is the best place to get started with Objects.

  2. The MDN tutorial isn’t bad either, so check it out if you need another take on the subject.

Intermediate/Advanced Array Magic

Besides being a quick and handy way to store data, arrays also have a set of functions for manipulating that data in very powerful ways. Once you begin to master these functions you will start to see ways to use them all over the place! There are really only a handful of these functions… but as you’ll soon see, the possibilities of what you can do with them are near endless.

Objectives of these section:

  • Learn about the forEach Array method

  • Learn about the filter Array method

  • Learn about the map Array method

  • Learn about the sort Array method

  • Learn about the reduce Array method

  1. Start out by watching the video JavaScript Array Cardio Practice – Day 1 from Wes Bos.

Duration: 24 minutes

To follow along clone the JavaScript30 repository.

  1. Watch and code with Part 2 of Wes Bos’s array series.

Duration: 8 minutes


You have been through a ton of content, and it would not be surprising if you were feeling rather overwhelmed at this point. Let’s take a little time to slow down and practice this stuff with more coding exercises. I’ll warn you now: some of these get pretty difficult, but if you’ve done the lessons you should have covered everything you need to know to solve them. Don’t be afraid to go back and review if you find that you can’t remember something, that’s part of the process. If you get stuck reach out for help in the usual channels.


Go to the Exercises Repository and follow the instructions on how to complete and submit the exercise.

Want MORE practice?

You really can’t spend too much time reviewing and practicing the fundamentals that we’ve covered here and luckily for you there are several websites that offer just this type of thing. Seriously, the better you grasp and the more fluently you can use the fundamental building blocks of JavaScript, the easier the hard stuff is going to come to you when we get to it. Take a minute to check out the following links.

  • Exercism – Uses a neat command-line interface to download and submit exercises and allows you to give and get feedback on your solutions.

  • CodeWars – A neat gamified system with leveled exercises. As you complete more exercises you level up and access more difficult ones.

  • HackerRank – Similar in setup to CodeWars, but this site is more focused on interview question type tasks. Some companies even use this site to interview candidates.

UPDATED: 12.11.2020