Since fetch() returns a promise, we can use the catch method of the promise to catch any error that occurs during the request or in the then callbacks:

fetch('./file.json')
.then(response => {
  // ...
})
.catch(err => console.error(err))

Another way of catching errors is to manage them in the first then:

fetch('./file.json')
.then(response => {
  if (!response.ok) { throw Error(response.statusText) }
  return response
})
.then(response => {
  // ...
})

Lessons in this unit:

0:	Introduction
1:	How to use Fetch
2:	▶︎ Catching errors in network requests
3:	The Response object
4:	Getting the body content
5:	The Request object
6:	Request headers
7:	POST requests