title: Babel doesn't convert fetch api code
body: <p>The fetch api is really helpful but unfortunately it doesn't work for most browsers especially internet explorer. I tried to convert my code from es6 to es5 using babel but it doesn't solve this issue. It still includes fetch when it is converted to es5. How can I get around this issue.
  Here is the es6 code: </p>
  
  <pre><code>var btnText = document.getElementById('btnText');
  var btnJson = document.getElementById('btnJson');
  btnText.addEventListener("click",fetchBtnText);
  function fetchBtnText() {
    fetch("sample.txt")
      .then((response) =&gt; response.text())
  .then((data) =&gt; console.log(data))
  }
  </code></pre>
  
  <p>Here is the conversion to es5</p>
  
  <pre><code>'use strict';
  var btnText = document.getElementById('btnText');
  var btnJson = document.getElementById('btnJson');
  btnText.addEventListener("click", fetchBtnText);
  function fetchBtnText() {
    fetch("sample.txt").then(function (response) {
      return response.text();
    }).then(function (data) {
      return console.log(data);
    });
  }
  </code></pre>