I recently purchased Just JavaScript by Dan Abramov and Maggie Appleton. I have panic-purchased various books about JavaScript before, but only managed to read a few chapters here and there. As a visual learner, I thought Just JavaScript would be a welcome break because I find it easier to remember a concept if I have an image, instead of a wall of text, to remember and return to.

Aside from Appleton’s incredible illustrations, the beauty of Just JavaScript is its hyper focus on what Abramov and Appleton refer to as your “mental model”—a metacognitive understanding of how you imagine the world of JavaScript. Metacognition, or thinking about one’s thinking, is a fundamental skill that all good learners employ sometimes explicitly and, more often, implicitly.

So, how does your brain think about learning a new language? In the background, you’re making continuous comparisons between your native language and the target language. You're constantly assessing if your own understanding of the target language is being supported or disproved by any current input. For us, the target language is: JavaScript. No worries that JavaScript is a computer language, your brain goes about learning in the same way, seeking patterns and building your fluency.

One of the challenges with the way many of us, especially my fellow coding bootcamp graduates, learned our first coding language is that there were many blanks our brain had to subconsciously fill in, in order to gain some beginner JavaScript fluency and actually start coding. Some of the linguistic rules we originally established in our mental model are completely incorrect. There is nothing inherently wrong with this, we have to make an educated guess at linguistic rules to move forward, but the way we correct these misconceptions matters!

You have to fill in the blanks until your brain gets more information, and this is where a lot of us can get stuck. As a former language teacher, the errors that were most important for me to correct were ones that a student made repeatedly because this was evidence to me that it was a part of the student’s mental model of the language that needed to be brought to their attention and intentionally changed. You need to start bringing some of these subconscious thoughts to a more conscious space and start thinking about your thinking.

The problem with beginner JavaScript students is that there is often no teacher present to see the errors you have inadvertently made as a part of your mental model of the language. But, metacognitive strategies such as deliberately investigating one’s understanding of a language can lead to self-correction and Just JavaScript does an expert job of not only raising awareness of one’s own mental model of JavaScript but, through repetition, taking the necessary to steps to correct it in many cases.

Credit: Maggie Appleton, "Just JavaScript," Example of mental model diagramming.

Abramov and Appleton’s short, 10-part, course asks you to repeatedly (and repeatedly, and repeatedly) physically diagram out the relationships between variables and data types. As depicted in the image above, Abramov and Appleton offer a mental model that visualizes the connection between a variable name and a value as a wire connecting the two.

Overall, my praise for Just JavaScript is overwhelmingly positive. It draws upon both solid linguistic and computer science fundamentals to create a helpful course for many JavaScript coders wishing to deepen their fluency and understanding of the language. Also, quite honestly, it’s fun! You get to draw!

Some specific topics that I personally found the most helpful were:

• the explanation of the difference between null versus undefined values,
• the complex role of objects within JavaScript,
• the implications behind the immutability of primitive values

The only two critiques I have of the course are, not surprisingly, the price: $42 is not cheap, especially due to the brevity of this course. Secondly, out of the 10 chapters in total, Chapter 4: “Studying from the Inside” dives deeper into the “universe” metaphor but at this point it seems unnecessary as the reader is already metaphorically and financially sold on the mental model that Abramov and Appleton offer.

For any beginner, especially my self-taught or bootcamp friends, I highly recommend Just JavaScript as it will help you begin the metacognitive process necessary to editing, and ultimately strengthening, your understanding of JavaScript. If you also purchased Just JavaScript, please let me know what you thought in the comments!