title: Babel not replacing arrow functions
body: <p>I installed babel cli and created a <code>.babelrc</code> file with <code>presets</code> set to <code>es2015</code>. I've also installed the <code>es2015</code> preset. But when I use the command <code>babel script.js --out-file script-compiled.js</code> and check the output file, I still find arrow function syntax (<code>=&gt;</code>) in the code, and browsers that don't support arrow functions are unable to run my code even though it has been transpiled with babel. What might be going on here? If it matters, the project is using react and I'm using browserify to create <code>app.js</code>, and then passing that file to babel.</p>
  
  <p>Edit: here's an example of code that isn't being properly converted:</p>
  
  <pre><code>  this._accountModel.fetch({
        success: (res) =&gt; {
          console.log('success');
        },
        error: () =&gt; {
          console.log('error');
        }
      });
  </code></pre>