How to represent arrays within ember-data models?

Question

Is it necessary to use DS.hasMany pointing to a DS.Model when a model contains an array? Even if the array elements are not really models (no IDs o

Answer 1

Here is an example of creating a custom array type in Ember-Data (version 10):

DS.JSONTransforms.array =

  # If the outgoing json is already a valid javascript array
  # then pass it through untouched. In all other cases, replace it
  # with an empty array.  This means null or undefined values
  # automatically become empty arrays when serializing this type.

  serialize: (jsonData)->
    if Em.typeOf(jsonData) is 'array' then jsonData else []


  # If the incoming data is a javascript array, pass it through.
  # If it is a string, then coerce it into an array by splitting
  # it on commas and trimming whitespace on each element.
  # Otherwise pass back an empty array.  This has the effect of
  # turning all other data types (including nulls and undefined
  # values) into empty arrays.

  deserialize: (externalData)->
    switch Em.typeOf(externalData)
      when 'array'  then return externalData
      when 'string' then return externalData.split(',').map((item)-> jQuery.trim(item))
      else               return []

Now you can use the custom type in a model attribute:

App.CalenderWeek = DS.Model.extend
  selected_days = DS.attr('array')

And now when you fetch a record with:

App.CalendarWeek.find(1)

both of these incoming json records will deserialize correctly into an Array:

{ selected_days: ['Monday', 'Tuesday', 'Saturday'] }

or

{ selected_days: 'Monday, Tuesday, Saturday' }