title: message.content.startswith is not a function
body: <p><strong>Here is my code:</strong></p>
  
  <pre><code>if (message.content.startswith(prefix+'ping')) {
      message.channel.sendmessage('pong! \'${date.now() -message.createdtimemestamp} ms\'');
  } else
  </code></pre>
  
  <p>It gives me an error</p>
  
  <p>TypeError: message.content.startswith is not a function</p>
  
  <p>What is the solution to this problem?</p>