check-nvmrc

Repository showing how to use a standalone Node.js script to let people know they're on the wrong Node.js version.

This is useful if you have external contributors, because they may get a difficult to understand error message if they try to install your project on an old version of Node.js.

Note: This project promotes nvm but you don't need to use nvm to use this approach, it just helps.

Output

This is what users will see when they pull your project locally and try to run npm install or npm start

If they're on a lower version (v4.0.0 vs v10.15.1)

You are using Node.js version 4.0.0 which we do not support. 

Please install Node.js version 10.15.1 and try again.

To do this you can install nvm (https://github.com/nvm-sh/nvm) then run `nvm install`.

If they're close to the same version (v10.0.0 vs v10.15.1))

Warning: You are using Node.js version 10.0.0 which we do not use. 

You may encounter issues, consider installing Node.js version 10.15.1.

To do this you can install nvm (https://github.com/nvm-sh/nvm) then run `nvm install`.

How to install

This repository has all the files necessary for this to work, here are the individual steps if you want them:

Copy bin/check-nvmrc.js into your project.
Copy .nvmrc into your project, and change the version to what you are using.
Add preinstall and prestart scripts to your package.json

{
  "scripts": {
    "preinstall": "node bin/check-nvmrc.js",
    "prestart": "node bin/check-nvmrc.js"
  }
}

(Optional) add an engines entry to package.json:

{
  "engines": {
    "node": "10.15.1"
  },
}

How's it work

The repostiory has a file called .nvmrc which the agreed version of Node.js to use for the team.

It is references a tool called nvm (Node Version Manager) that you can use to install different versions of Node.js

A standalone script will check the current version of Node.js being used against .nvmrc and warn people if they're not using the right version. This script is written with ES3/5 JavaScript that works in really old Node.js versions.

Why isn't this an npm dependency?

Older versions of Node.js can't npm install a newer projects files. So the script is written to work in older versions of Node.js without having any dependencies installed.