title: Else-If statements in JavaScript seem to cause some odd behaviour in Moment.js weekdays
body: <p>I'm using Moment.JS to check whether the current day is not a Sunday or a Saturday. If it isn't, then do some operation.</p>
  
  <p>Here's my code:</p>
  
  <pre><code>let currentDay = moment().weekday();
  
  if(currentDay !== 0 || currentDay !== 6){
       doSomeOperation();
    } else { console.log("we should get here on a Sunday"); }
  </code></pre>
  
  <p>This to me makes complete sense - if currentDay is not Sunday or Saturday then <code>doSomeOperation();</code> (For context, I'm running this on a Sunday.)</p>
  
  <p>However, it fails and it runs the <code>doSomeOperation();</code> method in the <code>if</code> block. I've run this in every combination possible but it still fails. I then decided to run them separately.</p>
  
  <pre><code>if(currentDay !== 0){
           doSomeOperation();
    } else { console.log('you should get here'); }
  </code></pre>
  
  <p>This succeeds - I get to the <code>else</code> block. This makes no sense - because if that succeeded, then why did the above fail? </p>
  
  <p>I finally changed it round to this:</p>
  
  <pre><code>if ((currentDay === 0 || currentDay === 6)){
  console.log('you should get here');
  } else { doSomeOperation() }
  </code></pre>
  
  <p>This succeeds and I print out 'you should get here'. If I invert the operators then all the checks pass. My question is what is it I'm doing wrong?</p>