Merge pull request #24217 from mfeckie/update-changed-attributes

Add typing for .changedAttributes()

types/ember-data/index.d.ts

@@ -23,6 +23,9 @@ declare module 'ember-data' {
     type AttributesFor<Model> = keyof Model; // TODO: filter to attr properties only (TS 2.8)
     type RelationshipsFor<Model> = keyof Model; // TODO: filter to hasMany/belongsTo properties only (TS 2.8)
 
+    export interface ChangedAttributes {
+        [key: string]: [any, any] | undefined;
+    }
     interface AttributeMeta<Model extends DS.Model> {
         type: keyof TransformRegistry;
         options: object;
@@ -500,7 +503,7 @@ declare module 'ember-data' {
              * Returns an object, whose keys are changed properties, and value is
              * an [oldProp, newProp] array.
              */
-            changedAttributes(): {};
+            changedAttributes(): ChangedAttributes;
             /**
              * If the model `hasDirtyAttributes` this function will discard any unsaved
              * changes. If the model `isNew` it will be removed from the store.

types/ember-data/test/model.ts

@@ -1,5 +1,5 @@
 import Ember from 'ember';
-import DS from 'ember-data';
+import DS, { ChangedAttributes } from 'ember-data';
 import { assertType } from "./lib/assert";
 
 const Person = DS.Model.extend({
@@ -30,3 +30,7 @@ assertType<Date>(user.get('createdAt'));
 
 user.serialize();
 user.serialize({ includeId: true });
+user.serialize({ includeId: true });
+
+const attributes = user.changedAttributes();
+assertType<ChangedAttributes>(attributes);