| # Contributing to Compiler Explorer |
| |
| First off, if you're reading this: thank you! Even considering contributing to |
| **Compiler Explorer** is very much appreciated! |
| Before we go too far, an apology: **Compiler Explorer** grew out of a bit of |
| hacky JavaScript into a pretty large and well-used project pretty quickly. |
| Not all the code was originally well-written or well-tested. |
| Please be forgiving of that. |
| |
| **Compiler Explorer** follows a [Code of Conduct](CODE_OF_CONDUCT.md) which |
| aims to foster an open and welcoming environment. |
| |
| # Where to start |
| |
| We have labeled issues which should be easy to do that you can find [here](https://github.com/compiler-explorer/compiler-explorer/issues?q=is%3Aopen+is%3Aissue+label%3A%22good+first+issue%22) |
| |
| If you have any questions, don't hesitate: [Contact us]. |
| |
| If there is something you would like to do yourself, it might help to make an issue so people can weigh in and point you in the right direction. |
| |
| |
| ## Node version |
| **Compiler Explorer** targets the latest [Node.js](https://nodejs.org/) LTS, |
| so it's better if you do so as well when testing your changes locally. |
| |
| Nonetheless, it _should_ run in everything post-Node.js 12.18. [Contact us] if |
| this is not the case for you. |
| |
| ## In brief |
| * Make your changes, trying to stick to the style and format where possible. |
| * We use [ESLint](https://eslint.org/) to ensure a consistent code base |
| and PRs won't pass unless it detects no errors. |
| * Running `make lint` will run the linter, which will auto-fix everything |
| it can and report back any errors and warnings. |
| * If adding a new server-side component please do your best to add a test to |
| cover it. For client-side changes that's trickier. |
| * Run the git hooks installer (_Only needed once_): `make install-git-hooks`. |
| This will automatically run the tests before you can commit, ensuring that |
| they pass before committing your changes. |
| _You can disable this check with `git commit --no-verify` if needed_. |
| * You can run `make check` to run both the linter and the code tests |
| * Do a smoke test: |
| Run `make` and ensure the site works as you'd expect. Concentrate on the |
| areas you'd expect to have changed, but if you can, click about generally to |
| help check you haven't unintentionally broken something else |
| * Submit a Pull Request. |
| |
| ## Basic code layout |
| |
| Code is separated into server-side code and client-side code. |
| All dependencies (server and client side) are installed via `package.json`. |
| _Server code_ is in `app.js` and in the `lib` directory. |
| _Client code_ is all in the `static` directory. |
| |
| In the server code, the `app.js` sets up a basic `express` |
| middleware-driven web server, delegating to the various compiler backends in |
| `lib/compilers/`. All of them inherit from `lib/base-compiler.js` which does |
| most of the work of running compilers, then parsing the output and forming a |
| JSON object to send to the client. Any assembly parsing is done in the |
| `lib/asm-parser.js`, and similar, files. |
| |
| In the client code, [GoldenLayout](https://www.golden-layout.com/) is used as |
| the container. If you look at some components like the |
| `static/compiler.js`, you'll see the general flow. |
| Any state stored makes it into the URL, so be careful not to stash |
| anything too big in there. |
| |
| The client code follows GoldenLayout's message-based system: |
| no component has a reference to any other and everything is done via messages. |
| This will allow us to use pop-out windows, if we ever need to, as the messages |
| are JSON-serializable between separate windows. |
| |
| ## Editing flow |
| |
| The recommended way to work on **Compiler Explorer** is to just run `make dev` |
| and let the automatic reloading do its magic. |
| Any changes to the server code will cause the server to reload, and any changes |
| to the client code will be reflected upon a page reload. |
| This makes for a pretty quick turnaround. |
| Note that a current issue makes every project media asset to be locally |
| unavailable. We will hopefully fix this in the near future. |
| |
| ## Gotchas |
| |
| * Stick to **ES5** (no `let` or arrow operators) in the client-side code. |
| Sadly there are still enough users out there on old browsers, |
| but feel free to use all the cool stuff on the server side code. |
| * Be aware that **Compiler Explorer** runs on a cluster on the live site. |
| No local state is kept between invocations, and the user's next request will |
| likely hit a different node in the cluster, so don't rely on |
| any in-memory state. |
| |
| [Contact us]: README.md#contact-us |