title: Data not updating on array
body: <p>I tried this http endpoint to update data on array call userArr, But any data wouldn't be updated</p>
  
  <pre><code>app.put('/update/:Id',function (req, res) {
  
  try{
  const index = userArr.findIndex(instence =&gt; instence.id == req.params.Id);
  userArr[index].firstName = req.body.fName;
  userArr[index].lastName = req.body.lName;
  userArr[index].birthDay = req.body.bDay;
  res.status(200).send(userArr[index]);
  }catch(e){
  res.status(500).send({message:e});
  }
  </code></pre>
  
  <p>Expected output is status 200 actual output is 500</p>