I'm getting “Uncaught (in promise) TypeError: Cannot read property 'data' of undefined” error in axios patch api

Question

I am trying to update an array of objects using an Axios/Node.js API. I have successfully created the array, but when I try to pass in through an axios patch request, I am getting the "Cannot read property 'data' of undefined". Anyone know what I might be doing wrong?

My axios function is below:

export const updateTrans = async (transArr) => {
try {      
const res = await axios({
  method: 'PATCH',
  url: `http://127.0.0.1:7000/api/v1/property/${id}`,
  data: { 
      "transactions": transArr  }
});
  
if (res.data.status === 'success') {
  showAlert('success', 'Data updated successfully!');

}
 } catch (err) {
console.log(err.response.data.message );

showAlert('error', err.response.data.message);
}
};

I have tried to stringify "transArr" as well, but still no luck.

Answer 1

The problem is that you're accessing err.response.data without checking if err.response exists. err.response is only present if the request was made and there was a response . If, for example, a CORS error or some network error occurred (or some other error inside the try block), it will not be present.

Just check that err.response exists before using it.

try {
  // ...
} catch (err) {
  console.log(err, err.response && err.response.data);

  if (err.response && err.response.data) {
    // The request was made and the server responded with a status code
    // that falls out of the range of 2xx
    showAlert("error", err.response.data.message);
    return;
  }

  showAlert("error", err.message);
}