Channels impl

channels/emoji.go

 package channels
 
+import (
+	"github.com/forPelevin/gomoji"
+	"github.com/pkg/errors"
+)
+
+var InvalidReaction = errors.New("The reaction is not valid, " +
+	"it must be a single emoji")
+
 // ValidateReaction checks that the reaction only contains a single Emoji
 func ValidateReaction(reaction string) error {
+	if len(gomoji.RemoveEmojis(reaction)) > 0 {
+		return InvalidReaction
+	}
+
+	if len(gomoji.FindAll(reaction)) != 1 {
+		return InvalidReaction
+	}
 
+	return nil
 }