promise_reject.js

/*
 * The promise "inner" should reject due to the ReferenceError that is inevitably thrown in line 13.
 * There is no reject handler for "inner", because it is called as part of another promise chain "outer".
 * However, the "outer" promise is being *resolved* and inner's rejection remains unhandled.
 * To make this more weird, if in line 16 instead of "inner", "Promise.reject()" is returned,
 * the outer promise will be rejected just fine.
 */

var inner = Promise.resolve(),
    outer = Promise.resolve();

inner.then(function() {
  return thisNameDoesNotExist;
});

outer.then(function() { return inner; })
  .then(function() { console.log("resolved"); }, function(e) { console.log("rejected", e); });