title: node.js is it save to replace process.env object?
body: <p>Say I have extend function that </p>
  
  <pre><code>extend(obj1, obj2) -&gt; creates new object does not mutate sources
  </code></pre>
  
  <p>According to documentation process.env is just an object, but I wonder is it save operation to do the followng:</p>
  
  <pre><code>process.env = extend(process.env, {MY_SETTING: 'Something'})
  </code></pre>
  
  <p>so process.env will be completely replaced new object with the same properties?</p>