A simple CoffeeScript Model base class providing declarative property support

model.coffee

# The Model base class

class Model
  prop = (k, props) -> (v) -> if v then props[k] = v else if v is null then delete props[k] else props[k]? or null
  @properties: (defaults) -> (@::[k] = prop k, (@::_props = {}))(v) for own k, v of defaults

# Example usage by a subclass

class Foo extends Model
  @properties
    bar: 'bar'

# Example usage of the subclass

foo = new Foo()
foo.bar()       # bar
foo.bar('baz')  # baz
foo.bar()       # baz
foo.bar(null)   # true
foo.bar()       # null