// Given this observable that will always error:
const source = button1.on('click').map((e, i) => {
  if (i === 2) {
    throw new Error('boom!');
  }
  return e;
});


// If we catch the error and return a different observable,
// the new observable takes over the subscription.
source.catch((err) => {
  console.error(err);
  // let another button take over
  return button2.on('click');
})
.subscribe({
  next: console.log,
  error: () => { /* never called */ }
});

// If we catch the error and return the same observable, you can
// resume or "retry" that observable
source.catch((err) => {
  console.log(err);
  return source;
})
.subscribe({
  next: console.log,
  error: () => { /* never called */ }
});

// If we catch the error and throw it again, or throw any other error
// The resulting observable still errors
source.catch((err) => {
  throw new Error('Different error!');
})
.subscribe({
  next: console.log,
  error: console.error
});