fix: DirectAccess skips JSON serialization causing undefined values in request and response

spec/ParseServerRESTController.spec.js

@@ -675,4 +675,22 @@ describe('ParseServerRESTController', () => {
     const result = await Parse.Push.getPushStatus(pushStatusId);
     expect(result.id).toBe(pushStatusId);
   });
+
+  it('should not convert undefined values to null on update with directAccess', async () => {
+    const createRes = await RESTController.request('POST', '/classes/MyObject', {
+      presentField: 'hello',
+    });
+    expect(createRes.objectId).toBeDefined();
+
+    await RESTController.request('PUT', `/classes/MyObject/${createRes.objectId}`, {
+      presentField: 'updated',
+      absentField: undefined,
+    });
+
+    const getRes = await RESTController.request('GET', `/classes/MyObject/${createRes.objectId}`);
+
+    expect(getRes.presentField).toBe('updated');
+    expect(getRes.absentField).toBeUndefined();
+    expect('absentField' in getRes).toBe(false);
+  });
 });

src/ParseServerRESTController.js

@@ -29,6 +29,19 @@ function getAuth(options = {}, config) {
   });
 }
 
+function stripUndefined(obj) {
+  if (obj === null || obj === undefined || typeof obj !== 'object' || Array.isArray(obj)) {
+    return obj;
+  }
+  const result = {};
+  for (const key of Object.keys(obj)) {
+    if (obj[key] !== undefined) {
+      result[key] = obj[key];
+    }
+  }
+  return result;
+}
+
 function ParseServerRESTController(applicationId, router) {
   function handleRequest(method, path, data = {}, options = {}, config) {
     // Store the arguments, for later use if internal fails
@@ -113,7 +126,7 @@ function ParseServerRESTController(applicationId, router) {
     return new Promise((resolve, reject) => {
       getAuth(options, config).then(auth => {
         const request = {
-          body: data,
+          body: stripUndefined(data),
           config,
           auth,
           info: {