title: Making one array exactly equal to another
body: <p>I have two arrays:</p>
  
  <pre><code>var array1 = [1, 2, 3];
  var array2 = [4, 5, 6];
  </code></pre>
  
  <p>I want array 1 to be exactly equal to array 2. I've been told I can't simply do:</p>
  
  <pre><code>array1 = array2;
  </code></pre>
  
  <p>If I can't do this, how can I make array1 equal to array2?</p>
  
  <p>Thanks</p>