title: What is the exact negation of if(variable) in javascript?
body: <p><strong>Context:</strong></p>
  
  <p>I often see in javascript programs the following conditional statement:</p>
  
  <pre><code>if (myVariable){
  ....
  }
  </code></pre>
  
  <p>As I understand do fat it tests against both undefined and null but I an not sure what else, I suppose against boolean false...</p>
  
  <p>Theoretically if I want to write the <em>exact</em> negation I can wrote</p>
  
  <pre><code>if (myVariable){
     // dummy empty
  }
  else{
     // My conditional code here
  }
  </code></pre>
  
  <p><strong>Question</strong></p>
  
  <p>What is the exact equivalent of the code above in the following simplest form?</p>
  
  <pre><code>if (&lt;what to write here using myVariable&gt;){
       // My conditional code here
  }
  </code></pre>
  
  <p>The answer <code>if (!myVariable)</code> seems too obvious, and I am not sure there are no traps here regarding undefined, null behaviours...</p>