rescript-relay is made up of these parts:
First thing's first - there's a suite of integration tests inside of /packages/rescript-relay/__tests__. The ambition is that these tests should cover everything needed to ensure RescriptRelay is working as intended. This includes the bindings, the language plugin and the PPX - everything. You run them by doing yarn test in /packages/rescript-relay.
Any feature added or fix done should consider whether that case is covered in the integration tests, and add tests for it if possible.
Please note that testing your local changes with the integration tests requires some recompiling. There's information on how to do that for each individual part below.
/packages/rescript-relay/src contains all the ReasonML code shipped in the package. You build it by running yarn bsb -make-world in /packages/rescript-relay.
bsconfig.json is only used for development, the actual bsconfig.json that'll be copied to the published package is located in bsconfig.release.json. This setup isn't great and it's likely that we'll move to using the same bsconfig.json for dev and release, with a script stripping unwanted things from the config before copying it to the release bundle.
The PPX is located in /packages/rescript-relay/rescript-relay-ppx and is built with esy.
The bulk of the PPX is located in /packages/rescript-relay/rescript-relay-ppx/library/Util.re. There's also some tests for the PPX located in /packages/rescript-relay/rescript-relay-ppx/test/TestFile.re.
Ensure you have esy installed by running npm install -g esy. Go to /packages/rescript-relay/rescript-relay-ppx and run esy. This will take some time as it bootstraps and compiles the project. After this finishes, the PPX will be built, and the relevant file will be located at /packages/rescript-relay/rescript-relay-ppx/_esy/default/build/default/bin/RescriptRelayPpxApp.exe.
The PPX is built in Azure for releases. Check out the release section below for details on that.
If you want to test your changes to the PPX using the integration tests, run esy in the PPX folder to build the PPX, and then run yarn bsb -clean-world && yarn bsb -make-world && yarn test in /packages/rescript-relay. This will clean and rebuild the tests before running them, ensuring that your changes to the PPX is picked up.
This a huge part of what RescriptRelay actually is. The language plugin takes the Flow types generated by the Relay compiler, and translates them to ReasonML types + does a number of other things like generate helpers and what not.
It's located in /packages/rescript-relay/language-plugin, and you build it by doing yarn build in that folder. It's part TypeScript, part ReasonML, so for active development of it you'll need to build using both. Most of the things that are regularly changed is in the ReasonML world, so running yarn bsb -make-world -w should be enough for most development.
The language plugin has a fairly comprehensive test suite that can be run by doing yarn test. The tests are sadly mostly snapshot tests, which can make them a bit hard to decipher, but as of now that's the way I felt has given the most "bang for the buck".
You can build the language plugin in full by running yarn build in the root folder of the language plugin. This will build and bundle the plugin.
It's a good idea to run the full integration tests after changing the language plugin. You can do that by first building the language plugin as described above, and then run yarn build:test in /packages/rescript-relay. It'll show an error message, but that's fine (and expectd).
Running yarn build:test will rerun the Relay compiler for the integration test suite using the newly built plugin. After that runs, you can run yarn test in /packages/rescript-relay/ again to run the integration tests with the changes you made.
This will be extended with some tips and tricks for deloping the language plugin at a later point.
The docs are located in /rescript-relay-documentation. It's built with Docosaurus, and to develop locally you simply do yarn && yarn start in that folder. Currently only @zth can do the prod release of this as it's tied to his now.sh account, but this may change in the future.
Doing a release isn't as automated as it should be right now. There's a script called build-ci.sh in the root folder which you can run to build the entire project for release (builds into /_release), except for the PPX. The PPX is built on Azure for Linux and Mac on push (sadly no Windows right now, but it should be easily fixable as soon as someone asks for it), so in addition to running ./build-ci.sh you'll need to download the built binaries from Azure and place them in /_release, named ppx-darwin for Mac and ppx-linux for Linux.
Preferably this could be automated fully using GitHub Actions or similar at some point.