Consider to naturally throw errors that occur in `map` callback

[medikoo]

Those callbacks are invoked immediately, and any crashes in them should be treated as programmer errors.

[medikoo]

This is off the table, for following reasons:

• Handling of callbacks among iterator functions should be consistent, and we have iterators that do not call callbacks immediatelly. That would mean eventual errors would be impossible to catch
• Above proposal also puts catch'ing errors in then callbacks in question, we may also ask user to deal with operational errors by returning rejected promises and not throwing, and that would be make very controversial design decision (to design which is already widely accepted).

Putting it simply if it cannot be both consistent with other methods and make programming errors being catchable it's no-go.