pick random user from support slack channel

example.coffee

module.exports = (robot) ->
  robot.respond /get help/i, (res) ->
    # get channel list from slack, might require some extra filtering if there's lot of them
    robot.http("https://slack.com/api/channels.list?token=#{process.env.HUBOT_SLACK_TOKEN}")
      .header('Accept', 'application/json')
      .get() (err, response, body) ->
        channels = JSON.parse(body).channels
        supportChannelMembers = channels.filter((c) => c.name == 'support')[0].members

        # filter users by channel and status
        users = Object.entries(res.robot.adapter.client.rtm.dataStore.users)
        activeUsers = users.filter((v) => supportChannelMembers.includes(v[0]) && v[1].presence == 'active')
                           .map((v) => v[1])
        
        # pick random user
        randomActiveUser = activeUsers[Math.floor(Math.random() * activeUsers.length)]
        res.reply("Random developer for support request: @#{randomActiveUser.name}")