你想創(chuàng)建類和實(shí)例的方法。
class Songs
@_titles: 0 # Although it's directly accessible, the leading _ defines it by convention as private property.
@get_count: ->
@_titles
constructor: (@artist, @title) ->
@constructor._titles++ # Refers to <Classname>._titles, in this case Songs.titles
Songs.get_count()
# => 0
song = new Songs("Rick Astley", "Never Gonna Give You Up")
Songs.get_count()
# => 1
song.get_count()
# => TypeError: Object <Songs> has no method 'get_count'
class Songs
_titles: 0 # Although it's directly accessible, the leading _ defines it by convention as private property.
get_count: ->
@_titles
constructor: (@artist, @title) ->
@_titles++
song = new Songs("Rick Astley", "Never Gonna Give You Up")
song.get_count()
# => 1
Songs.get_count()
# => TypeError: Object function Songs(artist, title) ... has no method 'get_count'
Coffeescript 會(huì)在對(duì)象本身中保存類方法(也叫靜態(tài)方法),而不是在對(duì)象原型中(以及單一的對(duì)象實(shí)例),在保存了記錄的同時(shí)也將類級(jí)的變量保存在中心位置。