Messages.ts

[...]
const MessagesMutation: MessagesMutationResolvers = {
  async send(_, { input }) {
    const message = new MessageModel(input);
    await message.save();

    pubsub.publish(NEW_MESSAGE_EVENT, { message });

    sendPushNotification({
      title: input.senderName,
      body: message.text,
    });

    return message;
  }
};
[...]