Node.js and Version Managers

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This is one of those things, most developers (including me) just install and use without thinking about it. So, just doing quick-AI write-up to learn it.

What is Node.js?

Node.js is a JavaScript runtime built on Chrome's V8 JavaScript engine. It allows you to run JavaScript on your computer (outside of a web browser) and is commonly used for building web servers, APIs, command-line tools, and desktop applications.

Why do I need a Node.js version manager?

Different projects often require different versions of Node.js. Some older projects might need Node.js 14, while newer ones might require Node.js 18 or 20. A version manager lets you:

Install multiple Node.js versions on the same machine
Switch between versions easily for different projects
Avoid conflicts between project requirements
Keep your global Node.js installation clean

What are NVM and FNM?

NVM (Node Version Manager) - The original and most popular Node.js version manager

Written in bash
Works on macOS, Linux, and Windows (via WSL)
Mature and well-documented

FNM (Fast Node Manager) - A faster, modern alternative to NVM

Written in Rust
Significantly faster than NVM
Cross-platform (macOS, Linux, Windows)
Simpler codebase

Installing NVM

macOS/Linux

# Install via curl
curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.39.0/install.sh | bash

# Or via wget
wget -qO- https://raw.githubusercontent.com/nvm-sh/nvm/v0.39.0/install.sh | bash

# Reload your shell
source ~/.bashrc
# or
source ~/.zshrc

brew install fnm

Linux/macOS (via curl)

curl -fsSL https://fnm.vercel.app/install | bash

Windows (via Chocolatey)

choco install fnm

Windows (via Scoop)

scoop install fnm

Basic NVM Commands

# Install the latest LTS version
nvm install --lts

# Install a specific version
nvm install 18.17.0

# List installed versions
nvm list

# List available versions to install
nvm list-remote

# Switch to a version
nvm use 18.17.0

# Set a default version
nvm alias default 18.17.0

# Show current version
nvm current

# Uninstall a version
nvm uninstall 16.14.0

Basic FNM Commands

# Install the latest LTS version
fnm install --lts

# Install a specific version
fnm install 18.17.0

# List installed versions
fnm list

# List available versions to install
fnm list-remote

# Switch to a version
fnm use 18.17.0

# Set a default version
fnm default 18.17.0

# Show current version
fnm current

# Uninstall a version
fnm uninstall 16.14.0

Setting Up Shell Integration

NVM

Add to your ~/.bashrc or ~/.zshrc:

export NVM_DIR="$HOME/.nvm"
[ -s "$NVM_DIR/nvm.sh" ] && \. "$NVM_DIR/nvm.sh"
[ -s "$NVM_DIR/bash_completion" ] && \. "$NVM_DIR/bash_completion"

FNM

Add to your ~/.bashrc or ~/.zshrc:

# For bash
eval "$(fnm env --use-on-cd)"

# For zsh
eval "$(fnm env --use-on-cd)"

# For fish
fnm env --use-on-cd | source

Automatic Version Switching

Both NVM and FNM can automatically switch Node.js versions when you enter a project directory.

Using .nvmrc files

Create a .nvmrc file in your project root:

18.17.0

Then:

NVM: Run nvm use in the project directory
FNM: Will automatically switch if you have --use-on-cd enabled

Using package.json

FNM can also read the engines field in package.json:

{
  "engines": {
    "node": "18.17.0"
  }
}

Which should I choose: NVM or FNM?

Choose NVM if:

You want the most mature and widely-used option
You need extensive documentation and community support
You're working in a team that already uses NVM
You need features specific to NVM

Choose FNM if:

You want faster performance (especially on Windows)
You prefer modern tooling
You want automatic version switching via .nvmrc files
You're starting fresh and want the most efficient option

Common Workflows

Setting up a new project

# Navigate to your project
cd my-project

# Create .nvmrc file
echo "18.17.0" > .nvmrc

# Install and use the specified version
nvm install  # or fnm install
nvm use      # or fnm use

Switching between projects

# Project A (Node 16)
cd project-a
nvm use  # or fnm use

# Project B (Node 18)
cd project-b
nvm use  # or fnm use

Troubleshooting

Command not found after installation

Make sure you've reloaded your shell: source ~/.bashrc or source ~/.zshrc
Check if the installation added the necessary lines to your shell configuration
Try opening a new terminal window

NVM is slow on Windows

Consider using FNM instead, which is significantly faster on Windows
Or use nvm-windows, which is specifically designed for Windows

npm packages not found after switching versions

Each Node.js version has its own global npm packages
You'll need to reinstall global packages for each version
Consider using npx instead of global installs when possible

Version not switching automatically

Make sure you have shell integration set up correctly
For FNM, ensure you have the --use-on-cd flag in your shell configuration
Check that you have a .nvmrc file in your project root

Best Practices

General

Use .nvmrc files in your projects to specify Node.js versions
Keep your version manager updated
Use LTS (Long Term Support) versions for production projects
Document the required Node.js version in your project's README

Team Collaboration

Commit .nvmrc files to version control
Include Node.js version requirements in your project documentation
Consider using engines field in package.json

Performance

Don't install too many versions you don't need
Use FNM if you need better performance, especially on Windows
Consider using npx instead of global package installations

Migrating from NVM to FNM

Note your installed versions: nvm list
Install FNM
Install needed Node.js versions with FNM
Update your shell configuration to use FNM
Optionally remove NVM: rm -rf ~/.nvm

Alternative Version Managers

n - Simple Node.js version manager (macOS/Linux only)
volta - JavaScript tool manager (handles Node.js, npm, yarn)
asdf - Version manager for multiple languages (with Node.js plugin)

Getting Help

NVM: GitHub repository
FNM: GitHub repository
Check the respective documentation for detailed guides
Use nvm --help or fnm --help for command-specific help