title: Using curly braces in an array reduce function?
body: <p>If <code>fn3</code> is substituted for <code>fn2</code> in this example running in node 9.5.0 the <code>console.log(totalUpvotes)</code> will log <code>undefined</code>.  IIUC the result should be the same (92)?</p>
  
  <pre><code>    const posts = [{id: 1, upVotes: 2}, {id:2, upVotes: 89}, {id: 3, upVotes: 1}];
  
      const fn2 = (totalUpvotes, currentPost) =&gt; totalUpvotes + currentPost.upVotes;
  
      const fn3 = (totalUpvotes, currentPost) =&gt; {totalUpvotes + currentPost.upVotes}
  
      const totalUpvotes = posts.reduce(fn2, 0);
  
      console.log(totalUpvotes);
  </code></pre>