reaction content value targeting the given message.
space.send(reaction(emoji, message)) is the canonical form of
message.react(emoji). It resolves to the reaction Message
(content.type === "reaction") — keep it as the handle to unsend()
later. Resolves undefined only when the platform does not support
reactions (warned and skipped).
Accepts Message | undefined so space.send results chain without
narrowing (send resolves undefined when a platform skips unsupported
content); an undefined target throws at build time.
To react to a message known only by id, resolve it first via
space.getMessage(id).
Parameters
string
required
Returns
ReactionBuilder