Rejections and exceptions are the same thing to a promise. Don't try to catch() something if you have a second `.then(a, b)` function defined. Catch is just shorthand for `.then(undefined, function() {})`.

promise-exceptions.js

function promiseMe(exception) {
  return new Promise((resolve, reject) => {
    if (exception == 'exception') {
      throw new Error('problem');
    }

    reject(new Error('reject-called'));
  });
}

['exception', 'reject'].forEach((value) => {

  promiseMe(value)
    .then(() => {
      console.log('never happen');
    })
    .catch((err) => {
      console.log(1, value, 'catch', err.message);
    });

  promiseMe(value)
    .then(() => {
      console.log('never happen');
    })
    .then(undefined, (c) => {
      console.log(2, value, 'then.c', c.message);
    })
    .catch((err) => {
      console.log(2, value, 'catch', err.message);
    });

  promiseMe(value)
    .then(
      () => {
        console.log('never happen');
      },
      (b) => {
        console.log(3, value, 'then.b', b.message);
      },
    )
    .then(undefined, (c) => {
      console.log(3, value, 'then.c', c.message);
    })
    .catch((err) => {
      console.log(3, value, 'catch', err.message);
    });
});

/*
1 'exception' 'catch' 'problem'
2 'exception' 'then.c' 'problem'
3 'exception' 'then.b' 'problem'
1 'reject' 'catch' 'reject-called'
2 'reject' 'then.c' 'reject-called'
3 'reject' 'then.b' 'reject-called'
*/