Meteor - users online tracker

common.coffee

common =
  keepalive: ->
    (update = -> Meteor.call('keepalive') if Meteor.userId())()
    Meteor.clearInterval(Meteor.keepalive) if Meteor.keepalive?
    Meteor.keepalive = Meteor.setInterval(update, config.keepalive * 1000)

methods.coffee

Meteor.methods
  keepalive: (params) ->
    return false unless @userId
    Meteor.keepalive ?= {}
    Meteor.clearTimeout Meteor.keepalive[@userId] if Meteor.keepalive[@userId]
    (setOnline = (online) ->
      if (user = Meteor.user()) and not user.profile.online is online
        Meteor.users.update user._id, $set: {'profile.online': true}
    )(true)
    Meteor.keepalive[@userId] = Meteor.setTimeout (=>
      delete Meteor.keepalive[@userId]
      setOnline(false)
    ), (config.keepalive + 10) * 1000
    return true