async-map.md

1. Let O be this value.
2. If Type(O) is not Object or O does not have all the internal slots of a %AsyncIteratorPrototypeMapIteratorPrototype% Instance, return ! PromiseReject(a newly created TypeError object).
3. Let mapper be O.[[Mapper]].
4. Let iterated be O.[[Iterated]].
5. Let result be SubMap(iterated, v).
6. If result is an abrupt completion, return PromiseReject(result.[[Value]]).
7. Return PromiseResolve(result.[[Value]]).

SubMap(iterated, v)

1. Let nextPromise be ? IteratorNext(iterated, v)
2. Let next be ? Await(nextPromise)
3. Let done be ? IteratorComplete(next)
4. If done is true, then return ! CreateIterResultObject(undefined, true)
5. Let value be ? IteratorValue(next).
6. Let mapped be ? Await(? Call(mapper, undefined, « value »)).
7. Return CreateIterResultObject(mapped, false).