Homebrew Formula of yarn installing a build of my homebrew-global-prefix (fixing yarn's global prefix)

yarn.rb

class Yarn < Formula
  desc "JavaScript package manager"
  homepage "https://yarnpkg.com/"
  url "https://github.com/chrmoritz/yarn/releases/download/v0.28.4/yarn-v0.28.4.tar.gz"
  sha256 "de4fbd2b85b4a48bd68f6d1de7a05e54e15cc4a8ea73f2bbaae70bb57a2df2f5"

  bottle :unneeded

  depends_on "node" => :recommended

  def install
    libexec.install Dir["*"]
    bin.install_symlink "#{libexec}/bin/yarn.js" => "yarn"
    bin.install_symlink "#{libexec}/bin/yarn.js" => "yarnpkg"
    inreplace "#{libexec}/package.json", '"installationMethod": "unknown"', '"installationMethod": "homebrew"'
  end

  test do
    (testpath/"package.json").write('{"name": "test"}')
    system bin/"yarn", "add", "jquery"
  end
end