title: Verbose javascript conditional seeks simplification
body: <p>I have the following rather verbose conditional, I'm trying to wrap my head around a simpler version but I'm not getting anywhere.</p>
  
  <pre><code>if( agent % $.settings.gridSize === 0 &amp;&amp; value % $.settings.gridSize == 1 ){
      // Dud
  }else if(agent % $.settings.gridSize == 1 &amp;&amp; value % $.settings.gridSize === 0){
      // Dud
  }else{
      freeCells.push(value);
  }
  </code></pre>
  
  <p>Is there a way I can achieve the same condition with a single <code>if</code> statement, rather than using the throw-away <code>if else</code>?</p>
  
  <p>Something like:</p>
  
  <pre><code>if(!(a &amp;&amp; b) &amp;&amp; !(x &amp;&amp; y)){
     // Do stuff
  }
  </code></pre>