Indexer accepts arbitrary key to index by. Fix bug: Return an object instead of an array.

app/assets/javascripts/admin/services/indexer.js.coffee

@@ -6,8 +6,8 @@
 
 angular.module("ofn.admin").factory 'Indexer', ->
   new class Indexer
-    index: (data) ->
-      index = []
+    index: (data, key='id') ->
+      index = {}
       for e in data
-        index[e.id] = e
+        index[e[key]] = e
       index

spec/javascripts/unit/admin/services/indexer_spec.js.coffee

@@ -11,3 +11,12 @@ describe "indexer", ->
     objects = [{id: 1, name: 'one'}, {id: 2, name: 'two'}]
     index = Indexer.index objects
     expect(index).toEqual({1: {id: 1, name: 'one'}, 2: {id: 2, name: 'two'}})
+
+  it "indexes an array of objects by another field", ->
+    objects = [{widget_id: 1, name: 'one'}, {widget_id: 2, name: 'two'}]
+    index = Indexer.index objects, 'widget_id'
+    expect(index).toEqual({1: {widget_id: 1, name: 'one'}, 2: {widget_id: 2, name: 'two'}})
+
+  it "returns an object, not an array", ->
+    index = Indexer.index []
+    expect(index.constructor).not.toEqual(Array)