Corepack: the Node.js' manager of package managers
Tags: javascript, node, npm, docker
Published: 2021-09-09 13:23:43

Corepack is the new built-in tool for preparing the required package manager for our projects. Let's see what comes with this new package for packagers. 📦

## Installation

The new Node.js LTS v16 will be released at the end of October (without a fancy name assigned yet), it'll have [Corepack](https://github.com/nodejs/corepack) preinstalled in the default configuration since [v16.9.0](https://github.com/nodejs/node/releases/tag/v16.9.0). 👌

If we want to use this tool with previous versions we just need to install it as a global package:

```bash
$ npm install -g corepack
```

🧠 Remember that for now Corepack v0.9.0 only supports `pnpm`, `npm` and `yarn`.

## Basic usage

We can use the same package manager that we've always use in any machine without worrying if it's installed or not, using:

```bash
$ corepack pnpm install
```

Corepack will see to it that the required manager is ready to process your request.

### Specific versions

The included `npm` version with Node.js LTS v16 is v7, so what if we need `npm@6` for one project and `npm@7` for another?

Well, in this scenario you'll will find `corepack` very similar to [`nvm`](https://github.com/nvm-sh/nvm).

```bash
$ corepack prepare npm@6.14.15 --activate
$ node -v
v16.9.0
$ npm -v
7.21.1
$ corepack npm -v
6.14.15
```

🤯 So with `corepack prepare` you'll setup `npm@6`, and you can use it every time you need just by prefixing your `npm` usage with Corepack, e.g. `corepack npm ci`.

And your global `npm` command will continue untouched being `npm@7`.

🤔 But what is that `--activate` flag? Corepack will keep a cache of used versions of a packager, so you should activate the specific version that you want to use; otherwise you will still be using `npm@7` when you use `corepack npm -v`.

## Global package managers 🌎

What if I want `pnpm` as a global command in my terminal? You can enable Corepack to handle `pnpm` and automatically install it when is used for the first time:

```bash
corepack enable
```

Corepack will install the handlers in the node directory because it's in the `$PATH`, but you can use the destination of your choice:

```bash
corepack enable --install-directory path/to/bins_folder
```

And it's done, you can use `pnpm` or `yarn` directly:

```bash
$ pnpm -v
6.11.0
```

## Docker images

At the moment, the official Node.js images in Docker comes with `npm` and `yarn` preinstalled, but this may change in the near future. (no more `npm` and `yarn` preinstalled in the Docker image is possible! 🤯)

If you use `pnpm` in Docker you need to install it using `npm` or `curl`:

```bash
RUN npm install -g pnpm && pnpm install
```

Now Corepack is here to make this easier for you:

```bash
RUN corepack pnpm install
```

Or maybe you need a specific version like this:

```bash
RUN corepack prepare npm@6.14.15 --activate && corepack npm ci
```

## Conclusion

With Corepack we can have more control about which package manager we're using and we don't need to check if Node.js upgrades `npm` and we don't notice. Well, if that happens, by the time we realize that our application is on fire. 🔥

Also, `npm` is part of GitHub Inc. and it's not part of the Node.js governance, so it's a good decision if the Node.js project becomes agnostic and as developers we can use the package manager that we need without wasting space in our Docker images on packagers that we won't use.