pnpm support

[colincasey]

These changes build on top of existing corepack support to allow pnpm to be installed via Corepack.

The buildpack has also been modified use the pnpm binary at the following stages:

• installing dependencies
• running build scripts:
  • heroku-prebuild
  • build (or heroku-postbuild)
  • heroku-cleanup
• pruning dev dependencies

Usage

As stated in the Corepack docs, setting the package manager to be used is done using the packageManager field in package.json:

{
  "packageManager": "pnpm@<version>"
}

It is also possible to specify the pnpm version in the engines.pnpm field of package.json:

{
  "engines": {
    "pnpm": "<version>"
  }
}

Notes

• If the pnpm version is specified in both the packageManager and engines.pnpm field of package.json then the version specified in packageManager will be used and a warning will be displayed noting this.
• If there is a pnpm lockfile detected but no packageManager and engines.pnpm field defined in package.json then the buildpack will install the lastest version of pnpm.

---

The PRs listed below enhance this baseline support:

• Add pnpm caching #1225
• pnpm support (default version) #1226
• pnpm support engines #1227
• Multiple lockfiles error #1228
• pnpm support - periodic store pruning #1231
• Only prune when it's safe to do so #1238

[l-campbell]

Thanks for working on this @colincasey! So excited to be able to make use of these changes

[colincasey]

Thanks @l-campbell 😄

If you want to preview this in your application builds before it gets released, you can try it out today by swapping out the heroku/nodejs buildpack with one that references the pnpm_support branch:

heroku buildpacks:remove heroku/nodejs -a <your-appname>
heroku buildpacks:set https://github.com/heroku/heroku-buildpack-nodejs#pnpm_support -a <your-appname>

If you experience any build issues with pnpm during this preview phase, please file an issue and we'll do our best to address it before this PR is merged.

[l-campbell]

Working like a dream @colincasey 🚀 👏

Any idea when this will land?

[colincasey]

Good to hear, @l-campbell. Thanks for giving it a try 😄

I can't give a specific time-frame for the release but it will be soon. I just have a couple of documentation tasks to complete first.