Make a more generic solution: KeyValueMapStore

- As QueryPersistence, stored in the localStorage too but it is now more generic and has nothing to do with Query
 - Add some js unit testing

app/assets/javascripts/admin/orders/controllers/orders_controller.js.coffee

@@ -1,4 +1,4 @@
-angular.module("admin.orders").controller "ordersCtrl", ($scope, $timeout, RequestMonitor, Orders, SortOptions, $window, $filter, $location, QueryPersistence) ->
+angular.module("admin.orders").controller "ordersCtrl", ($scope, $timeout, RequestMonitor, Orders, SortOptions, $window, $filter, $location, KeyValueMapStore) ->
   $scope.RequestMonitor = RequestMonitor
   $scope.pagination = Orders.pagination
   $scope.orders = Orders.all
@@ -15,11 +15,11 @@ angular.module("admin.orders").controller "ordersCtrl", ($scope, $timeout, Reque
   $scope.poll = 0
   $scope.rowStatus = {}
 
-  QueryPersistence.storageKey = 'ordersFilters'
-  QueryPersistence.storableFilters = ["q", "sorting", "page", "per_page"]
+  KeyValueMapStore.localStorageKey = 'ordersFilters'
+  KeyValueMapStore.storableKeys = ["q", "sorting", "page", "per_page"]
 
   $scope.initialise = ->
-    unless QueryPersistence.restoreFilters($scope)
+    unless KeyValueMapStore.restoreValues($scope)
       $scope.setDefaults()
 
     $scope.fetchResults()
@@ -31,7 +31,7 @@ angular.module("admin.orders").controller "ordersCtrl", ($scope, $timeout, Reque
     }
 
   $scope.clearFilters = () ->
-    QueryPersistence.clearFilters()
+    KeyValueMapStore.clearKeyValueMap()
     $scope.setDefaults()
     $scope.fetchResults()
 
@@ -57,7 +57,7 @@ angular.module("admin.orders").controller "ordersCtrl", ($scope, $timeout, Reque
       per_page: $scope.per_page,
       page: page
     }
-    QueryPersistence.setStoredFilters($scope)
+    KeyValueMapStore.setStoredValues($scope)
     RequestMonitor.load(Orders.index(params).$promise)
 
   $scope.appendStringIfNotEmpty = (baseString, stringToAppend) ->

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

@@ -0,0 +1,29 @@
+angular.module("admin.indexUtils").factory 'KeyValueMapStore', (localStorageService)->
+  new class KeyValueMapStore
+    localStorageKey: ''
+    storableKeys: []
+
+    constructor: ->
+      localStorageService.setStorageType("sessionStorage")
+
+    getStoredKeyValueMap: ->
+      localStorageService.get(@localStorageKey) || {}
+
+    setStoredValues: (source) ->
+      keyValueMap = {}
+      for key in @storableKeys
+        keyValueMap[key] = source[key]
+      localStorageService.set(@localStorageKey, keyValueMap)
+
+    restoreValues: (target) ->
+      storedKeyValueMap = @getStoredKeyValueMap()
+      
+      return false if _.isEmpty(storedKeyValueMap)  
+      
+      for k,v of storedKeyValueMap
+       target[k] = v
+
+      return true
+
+    clearKeyValueMap: () ->
+      localStorageService.remove(@localStorageKey)

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

@@ -1,30 +0,0 @@
-angular.module("admin.indexUtils").factory 'QueryPersistence', (localStorageService)->
-  new class QueryPersistence
-    storageKey: ''
-    storableFilters: []
-
-    constructor: ->
-      localStorageService.setStorageType("sessionStorage")
-
-    getStoredFilters: ->
-      localStorageService.get(@storageKey) || {}
-
-    setStoredFilters: (scope) ->
-      filters = {}
-      for key in @storableFilters
-        filters[key] = scope[key]
-      localStorageService.set(@storageKey, filters)
-
-    restoreFilters: (scope) ->
-      storedFilters = @getStoredFilters()
-
-      unless _.isEmpty(storedFilters)
-        for k,v of storedFilters
-          scope[k] = v
-
-        return true
-
-      false
-
-    clearFilters: () ->
-      localStorageService.remove(@storageKey)

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

@@ -0,0 +1,38 @@
+describe "Test KeyValueMapStore service", ->
+
+  KeyValueMapStore = null
+  
+  beforeEach ->
+    module "ofn.admin"
+
+  beforeEach inject (_KeyValueMapStore_) ->
+    KeyValueMapStore = _KeyValueMapStore_
+
+  it "set and restore filters", ->
+    KeyValueMapStore.localStorageKey = 'localStorageKey'
+    KeyValueMapStore.storableKeys = ["a", "b", "c"]
+    source =
+      a: "1",
+      b: "2",
+      d: "4"
+    KeyValueMapStore.setStoredValues(source)
+    source = {}
+    restored = KeyValueMapStore.restoreValues(source)
+    expect(restored).toEqual true
+    expect(source).toEqual {a: '1', b: '2'}
+
+  it "clear filters", ->
+    KeyValueMapStore.storageKey = 'localStorageKey'
+    KeyValueMapStore.storableFilters = ["a", "b", "c"]
+    source =
+      a: "1",
+      b: "2",
+      d: "4"
+    KeyValueMapStore.setStoredValues(source)
+    KeyValueMapStore.clearKeyValueMap()
+    source = {}
+    restored = KeyValueMapStore.restoreValues(source)
+    expect(restored).toEqual false
+    expect(source).toEqual {}
+
+