reactivity

This repository is the result of my attempt to understand how SolidJS reactivity works.

It provides the following methods: createSignal, createEffect, createMemo, createRoot, getContext, setContext, onDispose, onError, untrack, tick, getOwner and runWithOwner.

Developing

This repository uses deno as runtime, because of its good integration with Typescript and its built-in test runner.

Testing

For running the tests, run deno task test. This will generate a coverage report under cov_profile

Coverage

For printing the coverage, run deno task coverage

The journey

As stated above, this repository started out as an attempt to understand how the reactive core of SolidJS works, but as I was not able to grasp it by looking at the SolidJS implementation, I had to find different sources. The first and easiest explanation I found is this article from Ryan Carniato, the creator of SolidJS, on dev.to:

Building a reactive library from scratch

But, as he mentions in his write-up, the system used in SolidJS is much more complicated. After some search, I found flimsy:

A single-file <1kb min+gzip simplified implementation of the reactive core of Solid, optimized for clean code.

The annotated source code really helped me to get an understanding of how a more advanced reactivity system could look like.

But after a few days in which I had implemented flimsy step by step myself to understand it, I found out about reactively and its attempt on lazy memos. It took me some time to implement them and in the time of doing it I found the implementation of MaverickJS which helped me much, as it also provides a scheduler to execute effects.

This repository and my current understanding of reactivity was only made possible by these implementations and of course their impelementors. Thanks to them!

For anyone who will get here and wants to understand how reactivity works, I will list my sources here again:

• Building a reactive library from scratch
• flimsy
• reactively
• @maverick-js/signals
• ...and of course now this repository 😉. I have made comments in the objects folder trying to make it understandable, but I recommend implementing your own system, as it makes it much easier to understand a complex subject like reactivity and will provide you more in-depth knowledge in the end