[parse] Adding original optional field to BeforeSaveRequest and overloading response.error (#23887)

* Missing request.original for Parse.Cloud

* Adding parameter to response.error function as it support 1 or 2 parameters

* restoring original state

* fixing cloud code response.error signature. Supporting 2 arguments

* Missing `original` optional field in BeforeSaveRequest.

* Testing `request.original` and the two possible formats of response.erro

types/parse/index.d.ts

@@ -891,7 +891,8 @@ declare namespace Parse {
 
         interface FunctionResponse {
             success: (response: any) => void;
-            error: (response: any) => void;
+            error (code: number, response: any): void;
+            error (response: any): void;
         }
 
         interface Cookie {
@@ -912,7 +913,9 @@ declare namespace Parse {
         interface AfterDeleteRequest extends TriggerRequest { }
         interface BeforeDeleteRequest extends TriggerRequest { }
         interface BeforeDeleteResponse extends FunctionResponse { }
-        interface BeforeSaveRequest extends TriggerRequest { }
+        interface BeforeSaveRequest extends TriggerRequest {
+            original?: Parse.Object;
+        }
         interface BeforeSaveResponse extends FunctionResponse {
             success: () => void;
         }
@@ -1147,4 +1150,4 @@ declare module "parse/node" {
 declare module "parse" {
     import * as parse from "parse/node";
     export = parse
-}
+}

types/parse/parse-tests.ts

@@ -385,6 +385,27 @@ function test_cloud_functions() {
         // result
     });
 
+    const CUSTOM_ERROR_INVALID_CONDITION = 1001
+    const CUSTOM_ERROR_IMMUTABLE_FIELD = 1002
+
+    Parse.Cloud.beforeSave('MyCustomClass', (request: Parse.Cloud.BeforeSaveRequest,
+        response: Parse.Cloud.BeforeSaveResponse) => {
+            
+            if (request.object.isNew()) {
+                if (!request.object.has('immutable')) return response.error('Field immutable is required')
+            } else {
+                const original = request.original;
+                if (original == null) { // When the object is not new, request.original must be defined
+                    return response.error(CUSTOM_ERROR_INVALID_CONDITION, 'Original must me defined for an existing object')
+                }
+
+                if (original.get('immutable') !== request.object.get('immutable')) {
+                    return response.error(CUSTOM_ERROR_IMMUTABLE_FIELD, 'This field cannot be changed')
+                }
+            }
+            response.success()
+    });
+
     Parse.Cloud.beforeFind('MyCustomClass', (request: Parse.Cloud.BeforeFindRequest) => {
         let query = request.query; // the Parse.Query
         let user = request.user; // the user