Rocket.Chat/app/utils/server/lib/composeMessageObjectWithUser.js

import { Users } from '/app/models';
import { settings } from '/app/settings';

const getUser = (userId) => Users.findOneById(userId);

export const composeMessageObjectWithUser = function(message, userId) {
	if (message) {
		if (message.starred && Array.isArray(message.starred)) {
			message.starred = message.starred.filter((star) => star._id === userId);
		}
		if (message.u && message.u._id && settings.get('UI_Use_Real_Name')) {
			const user = getUser(message.u._id);
			message.u.name = user && user.name;
		}
		if (message.mentions && message.mentions.length && settings.get('UI_Use_Real_Name')) {
			message.mentions.forEach((mention) => {
				const user = getUser(mention._id);
				mention.name = user && user.name;
			});
		}
	}
	return message;
};