title: How to use FileSystem.getInfoAsync() with Expo?
body: <p>I'm trying to test if a file exists with expo.</p>
  
  <p>This is the expo doc :
  <em>Returns
  If no item exists at this URI, returns { exists: false, isDirectory: false }. Else returns an object</em> </p>
  
  <pre><code>if (this._liste.length === 0) {
                 let tmp =FileSystem.getInfoAsync('file://exemple.json');
  
                  if(tmp.exists === false){
                      alert("not found")
                  }
              }
  </code></pre>
  
  <p>The File doesn't exist, I'm sure and the alert doesn't show.
  When I print tmp, I have a <strong>Object</strong> but when I print tmp.exist I have a <strong>undefined</strong>.</p>