diff --git a/app/assets/javascripts/admin/services/indexer.js.coffee b/app/assets/javascripts/admin/services/indexer.js.coffee
new file mode 100644
index 0000000000..a69f7f06e1
--- /dev/null
+++ b/app/assets/javascripts/admin/services/indexer.js.coffee
@@ -0,0 +1,13 @@
+# Convert an array of objects into a hash, indexed by the objects' ids
+#
+# producers = [{id: 1, name: 'one'}, {id: 2, name: 'two'}]
+# Indexer.index producers
+# -> {1: {id: 1, name: 'one'}, 2: {id: 2, name: 'two'}}
+
+angular.module("ofn.admin").factory 'Indexer', ->
+  new class Indexer
+    index: (data) ->
+      index = []
+      for e in data
+        index[e.id] = e
+      index
diff --git a/spec/javascripts/unit/admin/services/indexer_spec.js.coffee b/spec/javascripts/unit/admin/services/indexer_spec.js.coffee
new file mode 100644
index 0000000000..a7f009e7d3
--- /dev/null
+++ b/spec/javascripts/unit/admin/services/indexer_spec.js.coffee
@@ -0,0 +1,13 @@
+describe "indexer", ->
+  Indexer = null
+
+  beforeEach ->
+    module "ofn.admin"
+
+  beforeEach inject (_Indexer_) ->
+    Indexer = _Indexer_
+
+  it "indexes an array of objects by id", ->
+    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'}})