Prevent npm install for not supported Node.js versions

Yesterday I was reviewing a pull request to Contentful's Gatsby starter and learned a nifty little detail about npm configurations.

The goal of his pull request was to guarantee that people setting up the project use a specific Node.js version. You can define the engines property in your package.son to specify a version range.

{
  "engines": {
    "node": ">=12.0.0"
  }
}

A lot of projects define the property, but so far, I've never seen more than a little warning popping up when you run npm install. It turns out you can add a local npm configuration file (.npmrc) to your module/project root and explicitly turn on strict engine handling.

engine-strict=true

With this .npmrc in the project root, people are not able to run npm install if their Node.js is not fulfilling your requirements. 🎉

npm install
npm ERR! code ENOTSUP
npm ERR! notsup Unsupported engine for my-node-project@1.0.0: wanted: {"node":">=12.0"} (current: {"node":"10.20.1","npm":"6.14.4"})

FAIL 1

What about Yarn? Yarn doesn't need an additional configuration file and treats the engines property strictly by default.