title: What is the shortest way of checking if JS value exists?
body: <p>Assuming I have this :</p>
  
  <pre><code>var a = parseInt(prompt("Enter A"));
  var b = parseInt(prompt("Enter B"));
  var c = parseInt(prompt("Enter C"));
  </code></pre>
  
  <p>What  is the <em>shortest</em> way to check if a value exists in all 3 variables ?</p>
  
  <p>Doing    <code>if(a  &amp;&amp; b &amp;&amp; c)</code>  is <em>not</em> accurate cause <code>0</code> is falsy.</p>
  
  <p><em>p.s. <strong>a,b,c can be ints or strings</strong>...Also , There must be a trick here...</em></p>
  
  <p>for the string example  : </p>
  
  <pre><code>var a = (prompt("Enter A"));
  var b = (prompt("Enter B"));
  var c = (prompt("Enter C"));
  </code></pre>