Error in created hook: "ReferenceError: axios is not defined"

This error indicates that the axios library is not imported or defined in the file where the created hook is used. To fix this error, you need to import axios in the file where you are using it.

Here is an example of how to import axios in a Vue component:

<template>
  <div>
    <!-- Your component code here -->
  </div>
</template>

<script>
import axios from 'axios';

export default {
  name: 'MyComponent',
  created() {
    axios.get('/api/data')
      .then(response => {
        console.log(response.data);
      })
      .catch(error => {
        console.log(error);
      });
  }
}
</script>

<style>
/* Your component styles here */
</style>

In this example, we import axios using `import axios from 'axios';` at the beginning of the script section. We then use axios in the created hook to make an HTTP GET request to an API endpoint.