Class Methods and Instance Methods
Problem
You want to create class and instance methods.
Solution
Class Method
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'Instance Method
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'Discussion
Coffeescript will store class methods (also called static methods) on the object itself rather than on the object prototype (and thus on individual object instances), which conserves memory and gives a central location to store class-level values.