title: Right-hand side of instanceof is not callable
body: <p>So, i'm trying to make a simple Discord Bot using javascript, and I want to detect if a player username is on the banned list.
  I have an array</p>
  
  <pre><code>var banned = ['Andrew','David']
  </code></pre>
  
  <p>and an if</p>
  
  <pre><code>if (message.author.username instanceof banned) {.....
  </code></pre>
  
  <p>but when I run it, it outputs</p>
  
  <pre><code>if (message.author.username instanceof banned)
                              ^
  
  TypeError: Right-hand side of 'instanceof' is not callable
  </code></pre>
  
  <p>What can I do?</p>