Querysets in Backbone

queryset.coffee

define ['jquery', 'underscore', 'backbone'], ($, _, Backbone) ->
# The queryset iterator is a helper that builds iterator functions that allow simple string matching such as:
#     sample_iterator = (model) ->
#       return model.get(key) == value
  class QuerysetIterator
    constructor: (expressions) ->
      @expressions = expressions

    iterator: (model) ->
      for key, value in @expressions
        if model.get('key') == value
          return True


# The Queryset object is slighlty smarter than a list but not much. The big advantage is that it supports chainable filters.
#     qs = new Queryset({models: collection.models });
#     qs._filter(iterator).filter(iterator2)
#
# or you can use .filter for filtering with a certain attribute.
#     qs.filter({name:'John Doe'}) 

  class Queryset
    constructor: (options) ->
      @models = options['model']
      if @models[0]
        @collection = @models[0].collection
    models: []
    filter: (expressions) =>
      qsiterator = new Queryset(expressions)
      @_filter((model) ->
        qsiterator.iterator(model)
      )
     
    _filter: (iterator, context) =>
      new Queryset({models: _.filter(@models, iterator, context)})
    each: (iterator, context) =>
      _.each(@models, iterator, context)
  Queryset