title: Install Yarn after NPM
body: <p>I need some help and clarification regarding <strong>Yarn</strong> installation process.</p>
  
  <p>MacOS ver. 10.14.2</p>
  
  <ol>
  <li>I've installed <code>Homebrew</code> via official site (<code>ver. 2.0.1</code>).</li>
  <li>I've installed <code>NPM</code> by downloading package from official site (<code>ver. 10.15.1 LTS</code>).</li>
  <li>Now when I tried to install <code>yarn</code> via <code>brew install yarn</code></li>
  </ol>
  
  <p>I have the following error:</p>
  
  <pre><code>The post-install step did not complete successfully
  You can try again using `brew postinstall node`
  </code></pre>
  
  <p>As I undertand, NPM installs node locally, when, for instance, I try to use <code>create-react-app</code>. When I use Homebrew to install <code>yarn</code>, it tries to install <code>node</code> globally. And we have conflict here.</p>
  
  <p>I've found suggestion to use:</p>
  
  <pre><code>sudo chown -R `whoami`:admin /usr/local/ 
  </code></pre>
  
  <p>I am not entirely sure what this command does.</p>
  
  <p>So, the <strong>questions</strong> are:</p>
  
  <ol>
  <li>Why changing the owner of the folder should be a solution? How will it affect multi user system?</li>
  <li>What is the correct way to install yarn?</li>
  <li>Can be there any conflicts if node is installed globally and locally (app folder.)</li>
  </ol>
  
  <p><em>P.S.</em> Please correct me, if I have wrong understanding here.</p>