title: How to check if NOT using Javascript bitwise operators?
body: <p>I have a function that checks whether a user is premium by checking its flags:</p>
  
  <pre><code>isUserPremium() {
    return this.flags &amp; Flags.PREMIUM; // returns true
  }
  </code></pre>
  
  <p>Now let's say that I'd want another function, but this time to check whether the user is free, but using the same flag. I tried negating the returned value, but I'd like to know if there was a better way to do this.</p>
  
  <pre><code>isUserFree() {
    return !(this.flags &amp; Flags.PREMIUM); // returns false
  }
  </code></pre>