How can you track and handle an error that occurs when using a promise in the rejected state?

To track and handle errors when using a promise in the rejected state, you can use the .catch() method or the second argument of the .then() method.

Example using .catch():

fetch('https://api.example.com/data')
  .then(response => {
    if (!response.ok) {
      return Promise.reject('Network error');
    }
    return response.json();
  })
  .then(data => {
    console.log('Data:', data);
  })
  .catch(error => {
    console.error('An error occurred:', error);
  });

You can also use try...catch inside an asynchronous function with await:

async function getData() {
  try {
    const response = await fetch('https://api.example.com/data');
    if (!response.ok) {
      throw new Error('Network error');
    }
    const data = await response.json();
    console.log('Data:', data);
  } catch (error) {
    console.error('An error occurred:', error);
  }
}
getData();

Thus, error handling in the rejected state allows for proper response to failures and prevents application crashes.