Automatically generate PureScript documentation

by Taylor Fausak on

Recently I have been pouring a lot of time into PureScript projects. The canonical source for PureScript packages and documentation is Pursuit. It annoyed me that I had to manually generate and upload my documentation whenever I released a new version. So I figured out how to automate it and thought I’d share my workflow.

To get started, you’ll need a Personal Access Token from GitHub. You can create one at Make sure that you deselect all scopes. This token shouldn’t be allowed to do anything because it’s only used for authorization.

After you create it, copy the token and head over to Travis CI. you’ll want to add the token as an environment variable in your project’s settings. You can do that at Name your token GITHUB_TOKEN. Make sure that it is hidden in the build log so that other people can’t pretend to be you.

Now that your Travis build can authenticate as you on GitHub, it needs to generate and upload documentation. This isn’t something you want to do on every build, though. You only want documentation built when you release a new version. For PureScript packages, you make new versions with Git tags. Fortunately Travis runs a separate build for tags and it sets the TRAVIS_TAG environment variable for those builds. That means if TRAVIS_TAG is set, the build should generate and upload documentation.

So open up your .travis.yml and add an after_success section that looks like this:

- >-
  test $TRAVIS_TAG &&
  npm run psc-publish \
    | tail -n 1 \
    > output/documentation.json &&
  curl -X POST \
    -d @output/documentation.json \
    -H 'Accept: application/json' \
    -H "Authorization: token ${GITHUB_TOKEN}"

That does a lot, so here’s a breakdown:

  1. First it checks for the TRAVIS_TAG environment variable. If it’s not set, it won’t build documentation.

  2. Then it generates the documentation with psc-publish. For this to work, psc-publish must be in the "scripts" section of your package.json.

    • It is necessary to tail the output because npm run outputs garbage before the actual output of the script. Since psc-publish always outputs a single line of JSON, only the last line of the output is necessary.

    • The documentation must be written to a file that is ignored by Git. Otherwise psc-publish will complain that your Git working tree is dirty. Since most PureScript packages ignore the output directory, that’s a safe place to put the documentation.

  3. Finally it uploads to documentation to Pursuit. Pursuit itself recommends using curl -v, but that would be bad here because it would expose your GITHUB_TOKEN.

Now when you want to release a new version, all you have to do is create a new Git tag. Everything else will happen automatically!

If you want to see a complete, working example of this, check out Neon, one of my PureScript packages. You should be able to copy its package.json and .travis.yml into your own package. Take a look at this build to see how it looks on Travis.