All platforms (Mac, Linux, and Windows) 2024

If you just need to upgrade your old version of Node.js to the latest one and don't need multiple versions, simply overwrite your existing executable with the new one.

Download the latest Node.js from nodejs.org/en/download

This just Works! ^TM on all platforms and is the easiest/fastest method.
When you run node -v in your terminal, you will see the the latest version.

Mac

If you originally installed Node.js using Homebrew, then run:

brew upgrade node

Managing multiple versions of Node.js

If you need to run multiple versions of Node.js on your machine, e.g., if you have an older project that targets a specific version on AWS Lambda, then NVM (Node Version Manger) is your friend!

Step 1 - Get NVM

curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.39.3/install.sh | bash

If you're curious about the installation command, read the source code. It’s been reviewed by several Node.js security experts.

Step 2 - Install the specific version of Node.js you need

Once you've got NVM, you can install a specific version of Node.js using the nvm command:

nvm install v22.16.0

Note: you may need to close and reopen your terminal window for nvm command to be available.

You should expect to see something like this in your terminal:

Now using node v22.16.0

You now have the latest Node.js on your machine.
And if you need to temporarily switch to a different/previous version, you can do it with a simple nvm command.

Note: avoid using sudo with Node/NPM as it violates the security principle of least privilege.

NVM is considered better than N for managing multiple Node.js versions because the verbose commands mean it is much easier to keep track of what you are doing in your Terminal/SSH Log. It is used by the team at NPM, the creators/custodians of the Node.js world!

Use Node Version Manager (NVM)

It's a Bash script that lets you download and manage different versions of node. Full source code is here.

There is a separate project for nvm for Windows: github.com/coreybutler/nvm-windows

Below are the full steps to use NVM for multiple version of node on windows

1. download nvm-setup.zip extract and install it.
2. execute command nvm list available from cmd or gitbash or powershell, this will list all available version of node
3. use command nvm install version e.g. nvm install 12.14.0 to install on the machine
4. last once installed use nvm use version to use newer version e.g. nvm use 12.14.0

NodeSource provides binary distributions of Node.js; complete installation instructions can be found here. The instructions have been copied below for your reference. Instructions are the same for updating to the latest version.

Run once:

sudo apt-get update
sudo apt-get install -y ca-certificates curl gnupg
sudo mkdir -p /etc/apt/keyrings
curl -fsSL https://deb.nodesource.com/gpgkey/nodesource-repo.gpg.key | sudo gpg --dearmor -o /etc/apt/keyrings/nodesource.gpg

Run whenever you want to change the major version of Node.js:

NODE_MAJOR=20
echo "deb [signed-by=/etc/apt/keyrings/nodesource.gpg] https://deb.nodesource.com/node_$NODE_MAJOR.x nodistro main" | sudo tee /etc/apt/sources.list.d/nodesource.list
sudo apt-get update
sudo apt-get install nodejs -y

Prior to August 2023: Previously versions of this answer involved the use of a series of setup_XX.x scripts that you'd run to install/update Node.js:

curl -fsSL https://deb.nodesource.com/setup_current.x | sudo -E bash -
sudo apt-get install -y nodejs

But as @eis pointed out, these scripts are no longer supported. To see the previous answers, please look at the edit history for this answer.