title: Can't .join() function arguments - TypeError: undefined is not a function
body: <p>Minimum example: </p>
  
  <pre><code>function test() {
    console.log(arguments.join(','));
  }
  
  test(1,2,3);
  </code></pre>
  
  <p>I then get:</p>
  
  <blockquote>
    <p>TypeError: undefined is not a function</p>
  </blockquote>
  
  <p>However, when I do the same for an array:</p>
  
  <pre><code>console.log([1,2,3].join(','));
  </code></pre>
  
  <p>I get</p>
  
  <blockquote>
    <p>"1,2,3"</p>
  </blockquote>
  
  <p>As expected.</p>
  
  <p>What's wrong with arugments? It's suppose to be an array:</p>
  
  <pre><code>(function () {
    console.log(typeof [] == typeof arguments)
  })();
  </code></pre>
  
  <blockquote>
    <p>true</p>
  </blockquote>