node

Node Version Manager (nvm) for Windows

Manage multiple installations of node.js on a Windows computer.

tl;dr nvm, but for Windows, with an installer. Download Now!

There are situations where the ability to switch between different versions of Node.js can be very useful. For example, if you want to test a module you're developing with the latest bleeding edge version without uninstalling the stable version of node, this utility can help.

Installation & Upgrades

It comes with an installer (and uninstaller), because getting it should be easy. Please note, you need to uninstall any existing versions of node.js before installing NVM for Windows.

Download the latest installer from the releases.

To upgrade, run the new installer. It will safely overwrite the files it needs to update without touching your node.js installations. Make sure you use the same installation and symlink folder. If you originally installed to the default locations, you just need to click "next" on each window until it finishes.

Usage

NVM for Windows is a command line tool. Simply type nvm in the console for help. The basic commands are:

• nvm install <version>: Install a specific version, i.e. 0.10.32, or type latest for the latest stable version.
• nvm uninstall <version>: Uninstall a specific version.
• nvm use <version>: Switch to a specific version.
• nvm list: List the versions that are currently installed.
• nvm on: Enable nvm management.
• nvm off: Turn off nvm entirely (does not uninstall anything).
• nvm root <path>: Specify the root directory where different versions of node.js are stored. Leave blank to see the current root.

Gotcha!

Please note that any global npm modules you may have installed are not shared between the various versions of node.js you have installed. Additionally, some npm modules may not be supported in the version of node you're using, so be aware of your environment as you work.

Why another version manager?

There are several version managers for node.js. Tools like nvm and n only run on Mac OSX and Linux. Windows users are left in the cold? No. nvmw and nodist are both designed for Windows. So, why another version manager for Windows?

The architecture of most node version managers for Windows rely on .bat files, which do some clever tricks to set or mimic environment variables. Some of them use node itself (once it's downloaded), which is admirable, but prone to problems. Right around node 0.10.30, the installation structure changed a little, causing some of these to just stop working with anything new.

Additionally, some users struggle to install these modules since it requires a little more knowledge of node's installation structure. I believe if it were easier for people to switch between versions, people might take the time to test their code on back and future versions... which is just good practice.

What's the big difference?

First and foremost, this version of nvm has no dependency on node. It's written in Go, which is a much more structured approach than hacking around a limited .bat file. It does not rely on having an existing node installation. Plus, should the need arise, Go offers potential for creating a Mac/Linux version on the same code base with a substanially easier migration path than converting a bunch of batch to shell logic. bat > sh, it crazy, right?

The control mechanism is also quite different. There are two general ways to support multiple node installations with hot switching capabilities. The first is to modify the system PATH any time you switch versions, or bypass it by using a .bat file to mimic the node executable and redirect accordingly. This always seemed a little hackish to me, and there are some quirks as a result of this implementation.

The second option is to use a symlink. This concept requires putting the symlink in the system PATH, then updating its target to the node installation directory you want to use. This is a straightforward approach, and seems to be what people recommend.... until they realize just how much of a pain symlinks are on Windows. This is why it hasn't happened before.

In order to create/modify a symlink, you must be running as an admin, and you must get around Windows UAC (that annoying prompt). Luckily, this is a challenge I already solved with some helper scripts in node-windows. As a result, NVM for Windows maintains a single symlink that is put in the system PATH during installation only. Switching to different versions of node is a matter of switching the symlink target. As a result, this utility does not require you to run nvm use x.x.x every time you open a console window. When you do run nvm use x.x.x, the active version of node is automatically updated across all open console windows. It also persists between system reboots, so you only need to use nvm when you want to make a change.

NVM for Windows comes with an installer, courtesy of a byproduct of my work on Fenix Web Server.

Overall, this project brings together some ideas, a few battle-hardened pieces of other modules, and support for newer versions of node.

I also wrote a simple data feed containing a list of node.js versions and their associated npm version. This is how NVM for Windows recognizes the "latest" stable version. It's free for anyone to use.

Motivation

I needed it, plain and simple. Additionally, it's apparent that support for multiple versions is not coming to node core, or even something they care about. It was also an excuse to play with Go.

License

MIT.