Rocket.Chat/packages/rocketchat-slashcommands-msg/server.js

/*
* Msg is a named function that will replace /msg commands
*/

function Msg(command, params, item) {
	if (command !== 'msg' || !Match.test(params, String)) {
		return;
	}
	const trimmedParams = params.trim();
	const separator = trimmedParams.indexOf(' ');
	const user = Meteor.users.findOne(Meteor.userId());
	if (separator === -1) {
		return	RocketChat.Notifications.notifyUser(Meteor.userId(), 'message', {
			_id: Random.id(),
			rid: item.rid,
			ts: new Date,
			msg: TAPi18n.__('Username_and_message_must_not_be_empty', null, user.language)
		});
	}
	const message = trimmedParams.slice(separator + 1);
	const targetUsernameOrig = trimmedParams.slice(0, separator);
	const targetUsername = targetUsernameOrig.replace('@', '');
	const targetUser = RocketChat.models.Users.findOneByUsername(targetUsername);
	if (targetUser == null) {
		RocketChat.Notifications.notifyUser(Meteor.userId(), 'message', {
			_id: Random.id(),
			rid: item.rid,
			ts: new Date,
			msg: TAPi18n.__('Username_doesnt_exist', {
				postProcess: 'sprintf',
				sprintf: [targetUsernameOrig]
			}, user.language)
		});
		return;
	}
	const {rid} = Meteor.call('createDirectMessage', targetUsername);
	const msgObject = {
		_id: Random.id(),
		rid,
		msg: message
	};
	Meteor.call('sendMessage', msgObject);
}

RocketChat.slashCommands.add('msg', Msg);