Yarn wrapper script to use checked in yarn version without installing it globally

yarnw.sh

#!/usr/bin/env bash
#
# Wrapper script that executes the yarn version checked in in a project without
# requiring the global package to be available.
#
# This script uses nvm when a .nvmrc file is found next to it.
#
# Usage:
# - Place yarnw into the folder containing your .yarnrc / .yarnrc.yml file
#   pointing to a local yarn version.
# - Replace calls to yarn with calls to `./yarnw`
#
# Environment:
# - NVM_DIR: if set, and a .nvmrc is found next to this wrapper script, load nvm
#            from this folder instead of the default ~/.nvm
# - YARNW_SKIP_NVM: if set, yarnw ignores any nvmrc file
#
# @author Bram Gotink <bram@gotink.me> [https://github.com/bgotink]
# @license Public Domain
# @source https://gist.github.com/bgotink/6e56bbee5f1657b72aaf6c409486e8c4

# fail fast, fail hard
set -e

ROOT="$(cd "$(dirname "$0")" && pwd)"

function die {
  echo "$@" >&2
  exit 1
}

function has_command {
  command -v "$1" >/dev/null || return 1
}

function run_node {
  if [ -f "$ROOT/.nvmrc" ] && [ "_${YARNW_SKIP_NVM}" == "_" ]; then
    if ! has_command nvm; then
      local actual_nvm_dir="${NVM_DIR:-$HOME/.nvm}"

      if ! [ -d "$actual_nvm_dir" ] || ! [ -s "${actual_nvm_dir}/nvm.sh" ]; then
        die 'This repository contains a .nvmrc but nvm was not found'
      fi

      source "${actual_nvm_dir}/nvm.sh"
    fi

    cd "$ROOT"
    nvm use >/dev/null
    cd - >/dev/null 2>&1
  fi

  if has_command node; then
    exec node "$@"
  elif has_command nodejs; then
    exec nodejs "$@"
  else
    die 'No NodeJS found'
  fi
}

function parse_yarn_path_from_syml {
  local yarnrc="$ROOT/.yarnrc"

  if ! [ -f "$yarnrc" ]; then
    return 1
  fi

  grep -E '^yarn-path' "$yarnrc" | sed -e 's|^yarn-path||' -e 's|^:||' -e 's|^[[:space:]]*||' -e 's|"\(.*\)"|\1|'
}

function parse_yarn_path_from_yaml {
  local yarnrc="$ROOT/.yarnrc.yml"

  if ! [ -f "$yarnrc" ]; then
    return 1
  fi

  # Modified from https://stackoverflow.com/a/21189044
  local s='[[:space:]]*' w='[a-zA-Z0-9_]*' fs=$(echo @|tr @ '\034')
  sed -ne "s|^\($s\):|\1|" \
      -e "s|^\($s\)\($w\)$s:$s[\"']\(.*\)[\"']$s\$|\1$fs\2$fs\3|p" \
      -e "s|^\($s\)\($w\)$s:$s\(.*\)$s\$|\1$fs\2$fs\3|p" "$yarnrc" |
  awk -F$fs '{
    if (length($1) == 0) {
      if ($2 == "yarnPath") {
        printf("%s", $3);
      }
    }
  }'
}

yarn="$ROOT/$(parse_yarn_path_from_yaml || parse_yarn_path_from_syml || die 'No local yarn path found, use the global yarn instead of yarnw')"

YARN_IGNORE_PATH=1 run_node "$yarn" "$@"

z_LICENSE.md

The author disclaims copyright to this source code. In place of a legal notice, here is a blessing:

• May you do good and not evil.
• May you find forgiveness for yourself and forgive others.
• May you share freely, never taking more than you give.