title: Use functions fron another file, without require
body: <h2>Context:</h2>
  <p>I have 3 files, <code>parent.js</code>, <code>child1.js</code>, and <code>child2.js</code></p>
  <p><code>parent.js</code></p>
  <pre><code>let child1 = require(&quot;./child1.js&quot;)
  let child2 = require(&quot;./child2.js&quot;)
  let key = &quot;*****&quot;
  
  child1.start(key)
  child2.start();
  </code></pre>
  <p><code>child1.js</code></p>
  <pre><code>let key = false;
  
  module.exports = {
      action: async() =&gt; {
          return someApi.get(key);
      },
      start: async(_key) =&gt; {
          key = key;
      }
  }
  </code></pre>
  <p><code>child2.js</code></p>
  <pre><code>module.exports = {
      action: async() =&gt; {
          let res = await child1.action()
          ...
      },
      start: async() =&gt; {
          // startup actions
      }
  }
  </code></pre>
  <h2><strong>The Problem</strong></h2>
  <p>I need to run a function from <code>child1</code> inside <code>child2</code>, but I can't use <code>require</code> because there can only be 1 instance of <code>child1</code></p>
  <p>Does anyone know the solution for this? Thanks</p>