Replaced with MondoKit: We are excited to announce the next generation of GAE JS. Our ESM-only set of libraries, migrated from GAE JS and rebranded as MondoKit.

You can see a Migration guide from GAE JS to help you move to the new libraries. Many changes are simple search/replace.

We will continue to add minor fixes and patches to this library as required.

Find MondoKit on GitHub.

Use Cloud Datastore (or Firestore in Datastore Mode) as your app db including DataLoader implementation GraphQL and request level caching.


npm install @mondomob/gae-js-datastore



Initialise Datastore to be accessed elsewhere in your app.

// On app startup

// Anywhere else in your app
const datastore = datastoreProvider.get();
const key = datastore.key(["MyItem", "id123"]);
const [doc] = await datastore.get(key);


Dataloader implementation to help batch and cache db requests. Used internally by DatastoreRepository

// Apply middleware to create a new dataloader on each request


Access your collections through typed repositories.

Step 1: Define your entity

// Define your class schema
const demoItemSchema = t.type({
  id: t.string,
  name: t.string,

// Define your class type
type DemoItem = t.TypeOf<typeof demoItemSchema>;

// Initialise repository for the collection we want to access data in
const repository = new DatastoreRepository<DemoItem>("demo-items", {validator: demoItemSchema });

// OR define a custom class first
class DemoItemRepository extends DatastoreRepository<DemoItem> {
  constructor() {
    super("demo-items", { validator: demoItemSchema });
const repository = new DemoItemsRepository();

// Save an item
await{ id: "id123", name: "test item" });

// Get an item
const item = await repository.get("id123");

// Query items
const list = await demoItemsRepository.query();

// Reindex (re-save) all items in batches (200 by default)
const totalCount = await repository.reindexInBatches();
const totalCount = await repository.reindexInBatches({ batchSize: 1000 });

// Reindex (re-save) all items in batches with "quiet" mode (no logs written)
const totalCount = await repository.reindexInBatches({ quiet: true });

// Reindex (re-save) all items in batches, with a transformation per item
const totalCount = await repository.reindexInBatches({ transform: ({id, name}) => ({ id, name: `UPDATED ${name}` })});

// Reindex (re-save) all items at once (WARNING: Small datasets only)
const items = await repository.reindex();

// Reindex (re-save) all items at once (WARNING: Small datasets only), with a transformation per item (WARNING: Small datasets only)
const items = await repository.reindex(({id, name}) => ({ id, name: `UPDATED ${name}` }));


Annotate functions to make them transactional.

NOTE: Requires "experimentalDecorators": true set in your tsconfig.json

class UserService {
    public userRepo: DatastoreRepository<User>,
  ) {}

  async addCredits(userId: string, credits: number): Promise<User> {
    const user = this.userRepo.get(userId);
    user.credits = user.credits + credits;