Adds a function to the Object API

src/api/objects/MutableDomainObject.js

@@ -129,9 +129,7 @@ class MutableDomainObject {
 
         mutable.$observe('$_synchronize_model', (updatedObject) => {
             let clone = JSON.parse(JSON.stringify(updatedObject));
-            let deleted = _.difference(Object.keys(mutable), Object.keys(updatedObject));
+            utils.refresh(mutable, clone);
-            deleted.forEach((propertyName) => delete mutable[propertyName]);
-            Object.assign(mutable, clone);
         });
 
         return mutable;

src/api/objects/ObjectAPI.js

@@ -389,6 +389,23 @@ ObjectAPI.prototype.mutate = function (domainObject, path, value) {
     }
 };
 
+/**
+ * Updates a domain object based on its latest persisted state. Note that this will mutate the provided object.
+ * @param {module:openmct.DomainObject} domainObject an object to refresh from its persistence store
+ * @returns {Promise} the provided object, updated to reflect the latest persisted state of the object.
+ */
+ObjectAPI.prototype.refresh = async function (domainObject) {
+    const refreshedObject = await this.get(domainObject.identifier);
+
+    if (domainObject.isMutable) {
+        domainObject.$refresh(refreshedObject);
+    } else {
+        utils.refresh(domainObject, refreshedObject);
+    }
+
+    return domainObject;
+};
+
 /**
  * @private
  */

src/api/objects/ObjectAPISpec.js

@@ -223,6 +223,28 @@ describe("The Object API", () => {
             expect(testObject.name).toBe(MUTATED_NAME);
         });
 
+        it('Provides a way of refreshing an object from the persistence store', () => {
+            const modifiedTestObject = JSON.parse(JSON.stringify(testObject));
+            const OTHER_ATTRIBUTE_VALUE = 'Modified value';
+            const NEW_ATTRIBUTE_VALUE = 'A new attribute';
+            modifiedTestObject.otherAttribute = OTHER_ATTRIBUTE_VALUE;
+            modifiedTestObject.newAttribute = NEW_ATTRIBUTE_VALUE;
+            delete modifiedTestObject.objectAttribute;
+
+            spyOn(objectAPI, 'get');
+            objectAPI.get.and.returnValue(Promise.resolve(modifiedTestObject));
+
+            expect(objectAPI.get).not.toHaveBeenCalled();
+
+            return objectAPI.refresh(testObject).then(() => {
+                expect(objectAPI.get).toHaveBeenCalledWith(testObject.identifier);
+
+                expect(testObject.otherAttribute).toEqual(OTHER_ATTRIBUTE_VALUE);
+                expect(testObject.newAttribute).toEqual(NEW_ATTRIBUTE_VALUE);
+                expect(testObject.objectAttribute).not.toBeDefined();
+            });
+        });
+
         describe ('uses a MutableDomainObject', () => {
             it('and retains properties of original object ', function () {
                 expect(hasOwnProperty(mutable, 'identifier')).toBe(true);

src/api/objects/object-utils.js

@@ -165,12 +165,19 @@ define([
         return identifierEquals(a.identifier, b.identifier);
     }
 
+    function refresh(oldObject, newObject) {
+        let deleted = _.difference(Object.keys(oldObject), Object.keys(newObject));
+        deleted.forEach((propertyName) => delete oldObject[propertyName]);
+        Object.assign(oldObject, newObject);
+    }
+
     return {
         toOldFormat: toOldFormat,
         toNewFormat: toNewFormat,
         makeKeyString: makeKeyString,
         parseKeyString: parseKeyString,
         equals: objectEquals,
-        identifierEquals: identifierEquals
+        identifierEquals: identifierEquals,
+        refresh: refresh
     };
 });