Rocket.Chat/app/invites/server/functions/useInviteToken.js

import { Meteor } from 'meteor/meteor';

import { Invites, Users, Subscriptions } from '../../../models/server';
import { validateInviteToken } from './validateInviteToken';
import { addUserToRoom } from '../../../lib/server/functions/addUserToRoom';
import { roomTypes, RoomMemberActions } from '../../../utils/server';

export const useInviteToken = (userId, token) => {
	if (!userId) {
		throw new Meteor.Error('error-invalid-user', 'The user is invalid', { method: 'useInviteToken', field: 'userId' });
	}

	if (!token) {
		throw new Meteor.Error('error-invalid-token', 'The invite token is invalid.', { method: 'useInviteToken', field: 'token' });
	}

	const { inviteData, room } = validateInviteToken(token);

	if (!roomTypes.getConfig(room.t).allowMemberAction(room, RoomMemberActions.INVITE)) {
		throw new Meteor.Error('error-room-type-not-allowed', 'Can\'t join room of this type via invite', { method: 'useInviteToken', field: 'token' });
	}

	const user = Users.findOneById(userId);
	Users.updateInviteToken(user._id, token);

	const subscription = Subscriptions.findOneByRoomIdAndUserId(room._id, user._id, { fields: { _id: 1 } });
	if (!subscription) {
		Invites.increaseUsageById(inviteData._id);
	}

	// If the user already has an username, then join the invite room,
	// If no username is set yet, then the the join will happen on the setUsername method
	if (user.username) {
		addUserToRoom(room._id, user);
	}

	return {
		room: {
			rid: inviteData.rid,
			prid: room.prid,
			fname: room.fname,
			name: room.name,
			t: room.t,
		},
	};
};