title: npm - how to avoid duplicate node module installation for my "sandbox"?
body: <p>I have a "Sandbox" directory to test various node repositories. Each repository comes with its own <code>package.json</code> that requires me to run <code>npm</code> to install its dependencies. That leads to the same dependency modules being installed again and again. </p>
  
  <p>Is there a way to avoid this waste? 
  Ideally I would like all modules required by <code>package.json</code> of each repository down the directory tree to be installed in the top "Sadbox" directory or skipped if it is aleady there.</p>
  
  <p>So when I run <code>npm i</code> inside </p>
  
  <pre><code>Sandbox/repo1
  </code></pre>
  
  <p>it would check if a module from its <code>package.json</code> is already inside</p>
  
  <pre><code>Sandbox/node_modules/
  </code></pre>
  
  <p>and if yes and the version is compatible, it would skip that module.</p>
  
  <p>I have tried to use <code>dedupe</code> but this doesn't seem to work this way. </p>