readline1.coffee

    class ReadlineLoop
      constructor: ->
        @rl = readline.createInterface
          input:  process.stdin
          output: process.stdout
        @rl.on("line" , @onLine)
           .on("close", @onClose)
      onLine: => # ...
      onClose: => # ...

readline2.coffee

class ReadlineLoop
  actions =
    line:  "onLine"
    close: "onClose"
  constructor: ->
    @rl = readline.createInterface
      input:  process.stdin
      output: process.stdout
    for action,fn of actions
      @rl.on action, @[fn]
  onLine: => #...
  onClose: => #...

readline3.coffee

partial = (func, a...) -> (b...) ->
  func (for arg in a then arg ?= b.shift())...

class ReadlineLoop
  actions = [
    "live"
    "close"
  ]
  constructor: ->
    @rl = readline.createInterface
      input:  process.stdin
      output: process.stdout
    @rl.on(action, partial(action, @onAction)) for action in actions
  onAction: (action) =>
    switch action
      when "live"
        console.log("Live!")
      when "close"
        console.log("Closed!")
      else
        throw "Opps!"