Automatically switch to correct version of Node based on project

Question

Let's say I have 2 projects:

example1: requires node version 0.12.1
example2: requires node version 0.10

Currently, when I cd into each project, I use nvm use <version> before running the application.

Is there a way with node or nvm, to automatically switch to the needed version of node when I cd into each project?

Answer 1

Install Automatic Node Version Switching (avn) and add .node-version file that specifies the version you'd like to use with project. It automatically detects and uses it via installed version manager such as nvm and n.

Answer 2

You can add nvm command into package.json file

"scripts": {
  "preinstall": "nvm install 0.12.1",
  "prestart": "nvm use 0.12.1",
  "start": "node ./file1.js"
},

Also set desired version into package.json, so Continuous Integration services would know what version you want to use.

{
  "name": "naive",
  "description": "A package using naive versioning",
  "author": "A confused individual <iam@confused.com>",
  "dependencies": {
    "express": ">= 1.2.0",
    "optimist": ">= 0.1.0"
  },
  "engine": "node 0.4.1"
}

Answer 3

NPM now let's you specify the node version for a project like this npm install node@8.

So next time you do a npm ci or npm i, the correct version is automatically set.

Answer 4

If you're using a Bash shell, you can define a Bash alias to cd, which will do nvm install / nvm use for you when it detects a .nvmrc file.

alias cd='function cdnvm(){ cd $@; if [[ -f .nvmrc ]]; then <.nvmrc nvm install; fi; };cdnvm'

If you want to make the Node version to revert back to the default when you cd out of the directory, use the following alias:

alias cd='function cdnvm(){ cd $@; if [[ -f .nvmrc && -s .nvmrc  && -r .nvmrc ]]; then <.nvmrc nvm install; elif [[ $(nvm current) != $(nvm version default) ]]; then nvm use default; fi; };cdnvm'

Answer 5

Looks for a .nvmrc file in your current directory, every time you cd. If one is found, it loads the version via nvm use and throws out any output.

cd() {
  builtin cd "$@"
  if [[ -f .nvmrc ]]; then
    nvm use > /dev/null
  fi
}
cd .

Answer 6

There are also extended (user contributed) bash/zsh shell scripts in the NVM GitHub README:

bash script

Automatically call nvm use
This alias would search 'up' from your current directory in order to detect a .nvmrc file. If it finds it, it will switch to that version; if not, it will use the default version.

Put the following at the end of your $HOME/.bashrc:

find-up () {
    path=$(pwd)
    while [[ "$path" != "" && ! -e "$path/$1" ]]; do
        path=${path%/*}
    done
    echo "$path"
}

cdnvm(){
    cd "$@";
    nvm_path=$(find-up .nvmrc | tr -d '[:space:]')

    # If there are no .nvmrc file, use the default nvm version
    if [[ ! $nvm_path = *[^[:space:]]* ]]; then

        declare default_version;
        default_version=$(nvm version default);

        # If there is no default version, set it to `node`
        # This will use the latest version on your machine
        if [[ $default_version == "N/A" ]]; then
            nvm alias default node;
            default_version=$(nvm version default);
        fi

        # If the current version is not the default version, set it to use the default version
        if [[ $(nvm current) != "$default_version" ]]; then
            nvm use default;
        fi

        elif [[ -s $nvm_path/.nvmrc && -r $nvm_path/.nvmrc ]]; then
        declare nvm_version
        nvm_version=$(<"$nvm_path"/.nvmrc)

        declare locally_resolved_nvm_version
        # `nvm ls` will check all locally-available versions
        # If there are multiple matching versions, take the latest one
        # Remove the `->` and `*` characters and spaces
        # `locally_resolved_nvm_version` will be `N/A` if no local versions are found
        locally_resolved_nvm_version=$(nvm ls --no-colors "$nvm_version" | tail -1 | tr -d '\->*' | tr -d '[:space:]')

        # If it is not already installed, install it
        # `nvm install` will implicitly use the newly-installed version
        if [[ "$locally_resolved_nvm_version" == "N/A" ]]; then
            nvm install "$nvm_version";
        elif [[ $(nvm current) != "$locally_resolved_nvm_version" ]]; then
            nvm use "$nvm_version";
        fi
    fi
}
alias cd='cdnvm'

zsh script

Calling nvm use automatically in a directory with a .nvmrc file
Put this into your $HOME/.zshrc to call nvm use automatically whenever you enter a directory that contains an .nvmrc file with a string telling nvm which node to use:

# place this after nvm initialization!
autoload -U add-zsh-hook
load-nvmrc() {
  local node_version="$(nvm version)"
  local nvmrc_path="$(nvm_find_nvmrc)"

  if [ -n "$nvmrc_path" ]; then
    local nvmrc_node_version=$(nvm version "$(cat "${nvmrc_path}")")

    if [ "$nvmrc_node_version" = "N/A" ]; then
      nvm install
    elif [ "$nvmrc_node_version" != "$node_version" ]; then
      nvm use
    fi
  elif [ "$node_version" != "$(nvm version default)" ]; then
    echo "Reverting to nvm default version"
    nvm use default
  fi
}
add-zsh-hook chpwd load-nvmrc
load-nvmrc