p5.js provides way to create complex interactions compatible across devices with remarkable ease. The features p5js brings with such simplicity that it can be used by people with little or no coding knowledge. I saw the introductory video, presented by Lauren McCarthy and Daniel Shiffman, and liked the style and narrative, the library was presented with. The video was interactive, floating shapes in the video could be played with, while the video was still playing and I was also excited just by watching the excited presenters– by the way, Dan is always excited.
While there are libraries like Processing Java, Processing.js, D3.js, Easel.js, Three.js, Raphael.js, Kinetic.js, Paper.js, Famo.us js, Impact.js - which are subset, super-set (if combined) or precursors of p5js, having similar features but none so easy.
I've been using D3 for over 4 years, many times, it has facilitated me transforming some complex data in a meaningful way and it has helped me plotting the points on screen in a visually appealing way. It's a wonderful library with great capacity, armed with equally great documentation. However, there's a cognitive overhead of thinking in selections and update patterns. The selections and data(), enter(), exit() does add some cognitive overhead. Though, having used for so many times, I've been able to get the hang of it and now I like it a lot; the initial learning curve was very steep.
To whet your appetite, here are the full set of examples.
There are many applications where you could put p5js to work, e.g. making interactive versions of the types of figures you'd normally find in textbooks, and there's no one good library for this kind of thing. Each case is unique and has a large illustrative element, p5.js just allows you to get stuff done. Processing, from which p5js takes its inspiration, has an explicit goal of being beginner friendly. I think, simplicity is the reason, Processing made a splash in the artistic community too.
p5js defaults to either canvas or WebGL and uses abstractions, barely adding any overhead to raw JS. Where sensible it uses typed arrays internally.
On comparing notes, D3 uses SVG and DOM manipulation by default, and everything is trees of objects, consequently, creating data visualization is also done in an entirely different style. p5js uses a draw-loop for each frame, whereas d3 uses an enter/update/exit paradigm.
So unless you manually take steps to use the canvas (which is possible, but not the default), I doubt that d3 usually beats p5. But really, if you know how to write fast JS code, you can write fast p5 code. Remember, the examples presented are not necessarily the fastest possible code, since they are more about showing code examples.
p5js is an awesome library, If you're looking for ideas to play with, checkout Daniel Shiffman's Youtube Channel - Coding Train, a series in which he build ML libraries, games and lots of fun mini-projects. The channel has plenty of content teaching programming, visualization and graphics. Earlier the channel was named Coding Rainbow but now its Coding Train.
<x library> is a <word I don't know> for <task I'm not aware of> creating <word soup>, it's that easy!
Honestly, I think it's great way of showing what it can do as there were parts of the video that were interactive. The point is to show that p5js allows you to do interactive visual applications and an introductory video, showing that you can do that, is rather interesting. I checked out this editor and it is in the same spirit, this is how all instruction should be. There is no point in learning if doing is saved for a possible future.
Seems I put heaves of praise on p5, but everything has a flip side. Unfortunately, accessibility is going to be a concern. Rendering all the text on a canvas, even the links, makes it inaccessible to many people living with disability and since the learning domain is one of the playgrounds for this library, it won't cut the cake very nicely, Because any library or practice that is to be adopted by Schools or Universities has to consider the factors like Will someone from having minor sight issues to not able to see at all, be able to use this? Someone with minor hearing issues to someone not able to listen at all, all are users.
Then again, we have seen technologies standing on the shoulders of time, have a knack of overcoming limitations. Let's see if the excitement frizzles out or gains more momentum and spread.