title: switching from bower_components to node_modules crashes Polymer project
body: <p>I have a working Polymer project when I have all my links pointing to the bower_components folder, however, when I change to node_modules I get the following message when I run </p>
  
  <pre><code>polymer serve
  </code></pre>
  
  <p>"Failed to load resource: the server responded with a status of 404 (Not Found)"</p>
  
  <p>with the URL being:
  <a href="http://127.0.0.1:8081/node_modules/@polymer/polymer/polymer.html" rel="nofollow noreferrer">http://127.0.0.1:8081/node_modules/@polymer/polymer/polymer.html</a></p>
  
  <p>This is correct since the Polymer team changed polymer.html to polymer.js</p>
  
  <p>However, where is this done and how can I use polymer using yarn (which saves in node_modules)?</p>
  
  <p>Edit:</p>
  
  <p>I think I found the culprit. When I tried to find iron-icon<strong>s</strong> (mind the 's'), I could only find it on yarn which saves to node_modules. When I load the node module iron-icons I get the above-mentioned error message.</p>
  
  <p>So I point to the bower_component iron-icon (mind you, no 's') but that doesn't provide the extensive library of icons I have with the yarn package:</p>
  
  <p>on Yarn: <a href="https://yarnpkg.com/en/package/@polymer/iron-icons" rel="nofollow noreferrer">https://yarnpkg.com/en/package/@polymer/iron-icons</a> </p>
  
  <p>but no such thing with Bower: <a href="https://bower.io/search/" rel="nofollow noreferrer">https://bower.io/search/</a></p>
  
  <p>Why?!</p>