This snippet here:
response => response.json(),
// Do not use catch, because that will also catch
// any errors in the dispatch and resulting render,
// causing a loop of 'Unexpected batch number' errors.
error => console.log('An error occurred.', error)
I understand the warning not to use .catch(fn), since it swallows exceptions, but .then(_, fn), as used above, also swallows the exception.