vincej's avatar
Level 15

Uncaught (in promise) TypeError: Cannot read properties of undefined (reading 'headers')

I am converting from MIx to Vite and I am getting this problem. I have hunted around for a solution on SO and the internet at large. Nothing so far. Note: I am going to be using Svelte framework.

Any ideas anyone??

Many Thanks!

0 likes
4 replies
LaryAI's avatar
Level 58

This error typically occurs when you are trying to access a property of an undefined object. In this case, it seems like you are trying to access the 'headers' property of an undefined object.

To fix this issue, you need to ensure that the object you are trying to access the 'headers' property from is defined. You can do this by checking if the object exists before accessing its properties.

Here's an example of how you can handle this error in JavaScript:

// Assuming you have a promise that returns an object
yourPromise
  .then(response => {
    if (response && response.headers) {
      // Access the headers property
      console.log(response.headers);
    } else {
      throw new Error('Response or headers property is undefined');
    }
  })
  .catch(error => {
    console.error('Error:', error);
  });

In this example, we first check if the 'response' object exists and if it has the 'headers' property. If it does, we can safely access the 'headers' property. Otherwise, we throw an error to handle the case where the object or property is undefined.

Make sure to replace 'yourPromise' with the actual promise you are working with in your code.

If you are using async/await syntax, you can handle the error in a similar way:

async function yourFunction() {
  try {
    const response = await yourPromise;
    if (response && response.headers) {
      console.log(response.headers);
    } else {
      throw new Error('Response or headers property is undefined');
    }
  } catch (error) {
    console.error('Error:', error);
  }
}

yourFunction();

Again, replace 'yourPromise' with the actual promise you are working with in your code.

Remember to adapt this solution to your specific code and context.

jlrdw's avatar

Are you using await where needed?

vincej's avatar
Level 15

This is what I have. No I am not using await.


window.axios.defaults.headers.common['X-Requested-With'] = 'XMLHttpRequest';
window.axios.defaults.headers.common = {
    'X-Requested-With': 'XMLHttpRequest',
    'X-CSRF-TOKEN': $('meta[name="csrf-token"]').attr('content')
}
dmaloof's avatar

@vincej late but just change

window.axios = require('axios') 

to

import  axios from 'axios'
window.axios = axios;

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