title: Join an array with a block natively
body: <p>Is there a native way to join all elements of an array into a unique element like so:</p>
  
  <pre><code>[
    {a: "a"},
    {b: "b"}
  ].join do | x, y |
    x.merge(y)
  end
  </code></pre>
  
  <p>To output something like:</p>
  
  <pre><code>{
    a: "a",
    b: "b"
  }
  </code></pre>
  
  <p>The fact that I used hashes into my array is an example, I could say:</p>
  
  <pre><code>[
    0,
    1,
    2,
    3
  ].join do | x, y |
    x + y
  end
  </code></pre>
  
  <p>Ends up with <code>6</code> as a value.</p>