RT filename.

todolist_socketio_collaborate.coffee

#client端代码
#点击添加的时候
@socket.emit 'newItem', newItem if @socket

#点击加入的时候
    joinList: ->
        @socket = io.connect("http://localhost:3000")
        @socket.on 'connect', =>
            @socket.emit 'joinList', @$joinListName.val()
            @socket.on 'syncItems', (items) =>
                @syncItems(items)
    syncItems: (items) ->
        console.log 'syncing items'
        localStorage.clear()
        localStorage.setObj item.id. item for item in items
        @displayItems()

#server端代码 - 
#io.sockets代表所有可能接入server的sockets[来自client]的reference，
#所有'on-connect'和'in(room)'就好理解了
io.sockets.on 'connection', (socket) =>
    console.log 'connected'
    socket.on 'joinList', (list) =>
        console.log "joining list #{list}"
        socket.list = list
        socket.join(list)
        @todos[list] ?= []

        socket.emit 'syncItems', @todos[list]
        socket.on 'newItem', (todo) =>
            console.log 'newItem #{todo.title}'
            @todos[list].push todo
            io.sockets.in(socket.list).emit('itemAdded', todo)