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nvm/node: an easy way to use different versions for different projects

problem

I need to have different versions of node/npm for different projects.  I’d prefer to have each project “know” which version of node/npm it needs to use.


solution

prerequisites

Before we get started, there are a few prerequisites:

  • understand that this is a Mac solution.  While I’m sure a similar solution exists for Windows, I am neither knowledgeable enough nor inclined to write a compatible shell script for Windows at this time.
  • have/install nvm.  I installed mine with Brew.
  • have at least one version of node installed via nvm
  • have a basic understanding of terminal.
  • have a willingness to edit your .bash_profile.

gameplan

leveraging .nvmrc

Much like Ruby has a shortcut for setting the current version of Ruby to use, nvm has a similar feature.  When you enter the following command…

nvm use

… then nvm will look for a .nvmrc file and get the correct version number to use from there.  So first navigate to a project folder that uses node and create a new file called .nvmrc.  Inside just write 4.2.  If you’re a command-line geek then do the following:

cd <project folder>
touch .nvmrc # creates the file
echo \4.2 >> .nvmrc # appends the version to the file
cat .nvmrc # prints the file's contents

editing your .bash_profile

So the easiest way to make nvm read your .nvmrc file is to do a check when you change directories.  We need to make a function we can call when we cd into a directory:

All this is doing is

  • checking to see if the current directory matches the previous directory
  • if it doesn’t , then it stores the current directory to the previous’ variable
  • then it checks to see if a .nvmrc file exists
  • if so, then tell nvm to use it
  • lastly we tell the OS to call this command any time we do something in Terminal/Bash