user is typing feature

chat_rooms.coffee

jQuery(document).on 'turbolinks:load', ->
  u = $("#current_user").val()
  window.current_user = JSON.parse(u)
  messages = $('#messages')
  user_is_typing = $('#user_is_typing')

  App.global_chat = App.cable.subscriptions.create {
    channel: "ChatRoomsChannel"
    chat_room_id: messages.data('chat-room-id')
  },
  connected: ->
    # Called when the subscription is ready for use on the server

  disconnected: ->
    # Called when the subscription has been terminated by the server

  received: (data) ->
    if data.typing && current_user.id != data.user.id
      user_is_typing.html "#{data.user.email} is typing"
    else
      user_is_typing.html ""

  is_typing: (typing, chat_room_id) ->
    @perform 'is_typing', message: {typing: typing}, chat_room_id: chat_room_id
    
  $('textarea').on 'focus', (event) ->
    App.global_chat.is_typing true, messages.data('chat-room-id')
    return 

  $('textarea').on 'blur', (event) ->
    App.global_chat.is_typing false, messages.data('chat-room-id')
    return 

chat_rooms_channel.rb

class ChatRoomsChannel < ApplicationCable::Channel
  def subscribed
    stream_from "chat_rooms_#{params['chat_room_id']}_channel"
  end

  def unsubscribed
    # Any cleanup needed when channel is unsubscribed
  end
  
  def is_typing(data)
    ActionCable.server.broadcast "chat_rooms_#{params['chat_room_id']}_channel", typing: data['typing'], user: current_user
  end

end

Really helpful. Thanks!