title: 'fetch' is not defined.eslint(no-undef) in react-native
body: <p>I use fetch in react native and have a message : 'fetch' is not defined.eslint(no-undef) </p>
  
  <p>my code: </p>
  
  <pre><code>getData() {
  fetch('https://tutorialzine.com/misc/files/example.json', {})
    .then(res =&gt; res.json())
    .then((res) =&gt; {
      console.log(res);
    }).catch((e) =&gt; {
      console.log(e);
    });
  </code></pre>
  
  <p>}</p>
  
  <p>how can I fix it? and console.log not show data</p>