title: how to install package under (as) peerDependencies?
body: <p>I'm building a library and trying to understand how to install/specify a dependency under peerDependencies. </p>
  
  <p><a href="https://docs.npmjs.com/cli/install.html" rel="nofollow noreferrer">The npm docs don't talk about this under the command <code>npm install</code>:</a></p>
  
  <pre><code>npm install (with no args, in package dir)
  npm install [&lt;@scope&gt;/]&lt;name&gt;
  npm install [&lt;@scope&gt;/]&lt;name&gt;@&lt;tag&gt;
  npm install [&lt;@scope&gt;/]&lt;name&gt;@&lt;version&gt;
  npm install [&lt;@scope&gt;/]&lt;name&gt;@&lt;version range&gt;
  npm install &lt;git-host&gt;:&lt;git-user&gt;/&lt;repo-name&gt;
  npm install &lt;git repo url&gt;
  npm install &lt;tarball file&gt;
  npm install &lt;tarball url&gt;
  npm install &lt;folder&gt;
  
  alias: npm i
  common options: [-P|--save-prod|-D|--save-dev|-O|--save-optional] [-E|--save-exact] [-B|--save-bundle] [--no-save] [--dry-run]
  </code></pre>
  
  <p>Any help?</p>