How can i use a Backbone.Collection as optionValues for a Backgrid.SelectCell?

Question

I have a Backbone.Collection SprachLandList with a model SprachLand.

SprachLand

'use strict'
module.exports = class SprachLand extends Backbone.Model

SprachLandList

"use strict"
SprachLand = require('../models/SprachLand')
module.exports = class SprachLandList extends Backbone.Collection
model: SprachLand

I want to display another collection with Backgrid and this collection has a model with an attribute with an array of ids referencing the SprachLand models. Now i want to use the SprachlandList collection for the values of a Select2Cell cell in a Backgrid. Naively i tried

columns = [
  { name: "id", label: "ID", editable: false, cell: "integer" },
  { name: "bez", label: "Bezeichnung", editable: false, cell: "string" },
  { name: "rub.bez", label: "Rubrik", editable: false, cell: "string" },
  { name: "sl", label: "Sprachlandkombinationen", editable: true, cell:
      Backgrid.SelectCell.extend({
      #sllist is an instance of the SprachLandList
      optionValues: sllist 
      multiple: true
    })
}
]

I want the Select widget display the "bez" attribute" and have the "id" attribute as value.

Here is a JSON representation of sllist

"[{"id":1,"bez":"de-DE"},{"id":2,"bez":"fr-FR"},\ 
  {"id":3,"bez":"en-GB"},{"id":4,"bez":"nl-NL"},\ 
  {"id":5,"bez":"it-IT"},{"id":6,"bez":"de-CH"},\
  {"id":7,"bez":"fr-CH"},{"id":8,"bez":"it-CH"},\
  {"id":9,"bez":"de-AT"}]"

I get an error:

Uncaught TypeError: 'optionValues' must be of type {Array.<Array>|Array.<{name: string, values: Array.<Array>}>}

How can i get an acceptable representation of the SprachLandList collection for optionValues?

Answer 1

After some searching i found Converting Array of Objects into Array of Arrays

After some meddling i have now a possible solution:

columns = [
  { name: "id", label: "ID", editable: false, cell: "integer" },
  { name: "bez", label: "Bezeichnung", editable: false, cell: "string" },
  { name: "sl", label: "Sprachlandkombinationen", editable: true, cell: Backgrid.SelectCell.extend({
    optionValues: sllist.map((obj) ->
      nobj = obj.attributes
      Object.keys(nobj).sort().map (key) ->
        nobj[key]
    )
    formatter:
      fromRaw: (rawValue, model) ->
        (if _.isArray(rawValue) then rawValue else (if rawValue? then [rawValue] else []))
      toRaw: (formattedValue, model) ->
        (if not formattedValue? then [] else _.map(formattedValue, (v) ->             
          parseInt v
        ))
    multiple: true
    })
  }
  ]

The formatter is to convert the string values of the select element back to integers after edit.

Is this a correct solution?