Reaction

You react to the emoji on the message

Field

Field	Description
.Reaction	Returns reaction object which has following fields UserID, MessageID, Emoji.(ID/Name/...), ChannelID, GuildID. Emoji.ID is the ID of the emoji for custom emojis, and Emoji.Name will hold the unicode emoji if its a default one. (otherwise the name of the custom emoji).
.ReactionMessage	Returns the message object reaction was added to. {{range .ReactionMessage.Reactions}} {{.Count}} - {{.Emoji.Name}} {{end}} Returns emoji count and their name.
.ReactionAdded	Returns a boolean type bool true/false indicating whether reaction was added or removed.

Reaction object in Discord documentation (read this if you want to write complex codes).