Handling rejected promises

For a rejected promise, we have two ways of handling it: we can either use the second callback in the .then() method, or we can use the .catch() method. Here are the two versions available to us:

// alternative 1
getMoreData().then(
  data => { 
    console.log('data',data); 
  }, 
  err => { 
    console.log('error',err); 
  }
)

// alternative 2
getMoreData().then(data => {
  console.log('data', data);
})
.catch((err) => { 
  console.log('error', err); 
}); 

In the first case, we have a second callback added to the then() method, and in the second version, we chain a catch() method to the existing then() method. They are equivalent so you can use either one, but only one.