that uses
the registry API, is available.</li>
<li>The directories that npm uses, <code class="language-text">node_modules</code> (both locally and globally),
exist and can be written by the current user.</li>
<li>The npm cache exists, and the package tarballs within it aren't corrupt.</li>
</ul>
<p>Without all of these working properly, npm may not work properly.  Many issues
are often attributable to things that are outside npm's code base, so <code class="language-text">npm
doctor</code> confirms that th