Direnv project config handler for fnm (Fast Node Manager)

.envrc

# Automatically install fnm (Fast Node Manager) and the correct Node version.
# [fnm (Fast Node Manager)](https://github.com/Schniz/fnm) performs the same function as [nvm](https://nvm.sh/), but is a bit faster.
use_fnm() {
  local version_file="${1:-.nvmrc}"
  if ! has fnm; then
    if [[ "$OSTYPE" == darwin* ]] && has brew; then
      brew install fnm
    elif has cargo; then
      cargo install fnm
    elif has curl; then
      curl -fsSL https://fnm.vercel.app/install | bash
    elif has wget; then
      wget -qO- https://fnm.vercel.app/install | bash
    else
      echo "Could not determine a way to automatically install fnm (Fast Node Manager) for you."
      echo "Refer to the fnm readme for instructions on how to install it on your system: https://github.com/Schniz/fnm?tab=readme-ov-file#installation"
      return 1
    fi
    # Try to automatically load fnm from the shell config for ZSH or Bash.
    if [[ "$SHELL" == *zsh ]]; then
      add_fnm_eval ~/.zshrc
    elif [[ "$SHELL" == *bash ]]; then
      add_fnm_eval ~/.bashrc
      add_fnm_eval ~/.bash_profile
    else
      echo "Your shell '$SHELL' cannot automatically install fnm (Fast Node Manager)."
      echo "Refer to the fnm readme for instructions on how to install it on your system: https://github.com/Schniz/fnm?tab=readme-ov-file#installation"
      eval "$(fnm env --use-on-cd)"
    fi
  fi
  # Install the version configured in .nvmrc
  fnm install < "$version_file"
  # Get yarn with corepack, if the shell has no yarn available.
  if ! has yarn; then
    corepack enable yarn
  fi
  # Add “$PWD/node_modules/.bin” to the PATH environment variable. 
  layout node
}
add_fnm_eval() {
  local target_file="$1"
  if [[ -f "$target_file" ]]; then
    echo -e $'\neval "$(fnm env --use-on-cd)"\n' >> "$target_file"
    source "$target_file"
  else
    echo "Could not add fnm init to $target_file"
    eval "$(fnm env --use-on-cd)"
  fi
}

watch_file .nvmrc .node-version
[ -f .nvmrc ] && use_fnm .nvmrc
[ -f .node-version ] && use_fnm .node-version

fnm (Fast Node Manager) performs the same function as nvm, but is a bit faster.