@paralect/node-mongo

node-mongo

Lightweight reactive extension to official Node.js MongoDB driver.

Features

• ObjectId mapping. Automatically converts the _id field from the ObjectId to a string.
• ️️Reactive. Fires events as a document created, updated, or deleted from the database;
• CUD operations timestamps. Automatically sets createdOn, updatedOn, and deletedOn timestamps for CUD operations;
• Schema validation. Validates your data before saving;
• Paging. Implements high-level paging API;
• Soft delete. By default, documents don't remove from the collection, but are marked with the deletedOn field;
• Extendable. API is easily extendable, you can add new methods or override existing ones;
• Outbox support. node-mongo can create collections with _outbox postfix that stores all CUD events for implementing the transactional outbox pattern;

The following example shows some of these features:

import { eventBus, InMemoryEvent } from "@paralect/node-mongo";

await userService.updateOne({ _id: "62670b6204f1aab85e5033dc" }, (doc) => ({
  firstName: "Mark",
}));

eventBus.onUpdated(
  "users",
  ["firstName", "lastName"],
  async (data: InMemoryEvent<User>) => {
    await userService.atomic.updateOne(
      { _id: data.doc._id },
      { $set: { fullName: `${data.doc.firstName} ${data.doc.lastName}` } }
    );
  }
);

Installation

npm i @paralect/node-mongo

Connect to Database

Usually, you need to define a file called db that does two things:

• Creates database instance and connects to the database;
• Exposes factory method createService to create different Services to work with MongoDB;

import {
  Database,
  Service,
  ServiceOptions,
  IDocument,
} from "@paralect/node-mongo";

import config from "config";

const database = new Database(config.mongo.connection, config.mongo.dbName);
database.connect();

class CustomService<T extends IDocument> extends Service<T> {
  // You can add new methods or override existing here
}

function createService<T extends IDocument>(
  collectionName: string,
  options: ServiceOptions = {}
) {
  return new CustomService<T>(collectionName, database, options);
}

export default {
  database,
  createService,
};

Services

Service is a collection wrapper that adds all node-mongo features. Under the hood it uses Node.js MongoDB native methods.

createService method returns the service instance. It accepts two parameters: collection name and ServiceOptions.

import { z } from "zod";

import db from "db";

const schema = z
  .object({
    _id: z.string(),
    createdOn: z.date().optional(),
    updatedOn: z.date().optional(),
    deletedOn: z.date().optional().nullable(),
    fullName: z.string(),
  })
  .strict();

type User = z.infer<typeof schema>;

const service = db.createService<User>("users", {
  schemaValidator: (obj) => schema.parseAsync(obj),
});

export default service;

import userService from "user.service";

await userService.insertOne({ fullName: "Max" });

Schema validation

Node-mongo supports any schema library, but we recommend Zod, due to this ability to generate TypeScript types from the schemas.

Zod

const schema = z.object({
  _id: z.string(),
  createdOn: z.date().optional(),
  updatedOn: z.date().optional(),
  deletedOn: z.date().optional().nullable(),
  fullName: z.string(),
});

type User = z.infer<typeof schema>;

const service = createService<User>("users", {
  schemaValidator: (obj) => schema.parseAsync(obj),
});

Joi

const schema = Joi.object({
  _id: Joi.string().required(),
  createdOn: Joi.date(),
  updatedOn: Joi.date(),
  deletedOn: Joi.date().allow(null),
  fullName: Joi.string().required(),
});

type User = {
  _id: string;
  createdOn?: Date;
  updatedOn?: Date;
  deletedOn?: Date | null;
  fullName: string;
};

const service = createService<User>("users", {
  schemaValidator: (obj) => schema.validateAsync(obj),
});

Node-mongo validates documents before save.

Reactivity

The key feature of the node-mongo is that each create, update or delete operation publishes a CUD event.

• ${collectionName}.created
• ${collectionName}.updated
• ${collectionName}.deleted

Events are used to easily update denormalized data and also to implement complex business logic without tight coupling of different entities.

SDK support two type of events:

In-memory events

• Enabled by default;
• Events can be lost on service failure;
• Events are stored in eventBus (Node.js EventEmitter instance);
• For handling these events type you will use Events API;
• Designed for transferring events inside a single Node.js process. Events handlers listens node-mongo eventBus.

Transactional events

• Can be enabled by setting { outbox: true } when creating a service;
• Guarantee that every database write will produce an event;
• Events are stored in special collections with _outbox postfix;
• For handling these events type you will use watch (method for working with Change Streams) on the outbox table;
• Designed for transferring events to messages broker like Kafka. Events handlers should listen to message broker events (You need to implement this layer yourself).

On the project start, we recommend using in-memory events. When your application becomes tougher you should migrate to transactional events.

Service API

find

find(
  filter: Filter<T>,
  readConfig: ReadConfig & { page?: number; perPage?: number } = {},
  findOptions: FindOptions = {},
): Promise<FindResult<T>>

const { results: users, count: usersCount } = await userService.find({
  status: "active",
});

Fetches documents that matches the filter. Returns an object with the following fields(FindResult):

Field	Description
results	documents, that matches the filter
count	total number of documents, that matches the filter
pagesCount	total number of documents, that matches the filter divided by the number of documents per page

Pass page and perPage params to get a paginated result. Otherwise, all documents will be returned.

Parameters

• filter: Filter<T>;
• readConfig: ReadConfig & { page?: number; perPage?: number };
• findOptions: FindOptions;

Returns Promise<FindResult<T>>.

findOne

findOne(
  filter: Filter<T>,
  readConfig: ReadConfig = {},
  findOptions: FindOptions = {},
): Promise<T | null>

const user = await userService.findOne({ _id: u._id });

Fetches the first document that matches the filter. Returns null if document was not found.

Parameters

• filter: Filter<T>;
• readConfig: ReadConfig;
• findOptions: FindOptions;

Returns Promise<T | null>.

updateOne

updateOne: (
  filter: Filter<T>,
  updateFn: (doc: T) => Partial<T>,
  updateConfig: UpdateConfig = {},
  updateOptions: UpdateOptions = {},
): Promise<T | null>

const updatedUserWithEvent = await userService.updateOne(
  { _id: u._id },
  (doc) => ({ fullName: "Updated fullname" })
);

const updatedUser = await userService.updateOne(
  { _id: u._id },
  (doc) => ({ fullName: "Updated fullname" }),
  { publishEvents: false }
);

Updates a single document and returns it. Returns null if document was not found.

Parameters

• filter: Filter<T>;
• updateFn: (doc: T) => Partial<T>;
  Function that accepts current document and returns object containing fields to update.
• updateConfig: UpdateConfig;
• updateOptions: UpdateOptions;

Returns Promise<T | null>.

updateMany

updateMany: (
  filter: Filter<T>,
  updateFn: (doc: T) => Partial<T>,
  updateConfig: UpdateConfig = {},
  updateOptions: UpdateOptions = {},
): Promise<T[]>

const updatedUsers = await userService.updateMany(
  { status: "active" },
  (doc) => ({ isEmailVerified: true })
);

Updates multiple documents that match the query. Returns array with updated documents.

Parameters

• filter: Filter<T>;
• updateFn: (doc: T) => Partial<T>;
  Function that accepts current document and returns object containing fields to update.
• updateConfig: UpdateConfig;
• updateOptions: UpdateOptions;

Returns Promise<T[]>.

insertOne

insertOne: (
  object: Partial<T>,
  createConfig: CreateConfig = {},
  insertOneOptions: InsertOneOptions = {},
): Promise<T>

const user = await userService.insertOne({
  fullName: "John",
});

Inserts a single document into a collection and returns it.

Parameters

• object: Partial<T>;
• createConfig: CreateConfig;
• insertOneOptions: InsertOneOptions;

Returns Promise<T>.

insertMany

insertMany: (
  objects: Partial<T>[],
  createConfig: CreateConfig = {},
  bulkWriteOptions: BulkWriteOptions = {},
): Promise<T[]>

const users = await userService.insertMany([
  { fullName: "John" },
  { fullName: "Kobe" },
]);

Inserts multiple documents into a collection and returns them.

Parameters

• objects: Partial<T>[];
• createConfig: CreateConfig;
• bulkWriteOptions: BulkWriteOptions;

Returns Promise<T[]>.

deleteSoft

deleteSoft: (
  filter: Filter<T>,
  deleteConfig: DeleteConfig = {},
  deleteOptions: DeleteOptions = {},
): Promise<T[]>

const deletedUsers = await userService.deleteSoft({ status: "deactivated" });

Adds deletedOn field to the documents that match the query and returns them.

Parameters

• filter: Filter<T>;
• deleteConfig: DeleteConfig;
• deleteOptions: DeleteOptions;

Returns Promise<T[]>.

deleteOne

deleteOne: (
  filter: Filter<T>,
  deleteConfig: DeleteConfig = {},
  deleteOptions: DeleteOptions = {},
): Promise<T | null>

const deletedUser = await userService.deleteOne({ _id: u._id });

Deletes a single document and returns it. Returns null if document was not found.

Parameters

• filter: Filter<T>;
• deleteConfig: DeleteConfig;
• deleteOptions: DeleteOptions;

Returns Promise<T | null>.

deleteMany

deleteMany: (
  filter: Filter<T>,
  deleteConfig: DeleteConfig = {},
  deleteOptions: DeleteOptions = {},
): Promise<T[]>

const deletedUsers = await userService.deleteMany({ status: "deactivated" });

Deletes multiple documents that match the query. Returns array with deleted documents.

Parameters

• filter: Filter<T>;
• deleteConfig: DeleteConfig;
• deleteOptions: DeleteOptions;

Returns Promise<T[]>.

replaceOne

replaceOne: (
  filter: Filter<T>,
  replacement: Partial<T>,
  readConfig: ReadConfig = {},
  replaceOptions: ReplaceOptions = {},
): Promise<UpdateResult | Document>

await usersService.replaceOne({ _id: u._id }, { fullName: fullNameToUpdate });

Replaces a single document within the collection based on the filter. Doesn't validate schema or publish events.

Parameters

• filter: Filter<T>;
• replacement: Partial<T>;
• readConfig: ReadConfig;
• replaceOptions: ReplaceOptions;

Returns Promise<UpdateResult | Document>.

atomic.updateOne

updateOne: (
  filter: Filter<T>,
  updateFilter: UpdateFilter<T>,
  readConfig: ReadConfig = {},
  updateOptions: UpdateOptions = {},
): Promise<UpdateResult>

await userService.atomic.updateOne(
  { _id: u._id },
  { $set: { fullName: `${u.firstName} ${u.lastName}` } }
);

Updates a single document. Doesn't validate schema or publish events.

Parameters

• filter: Filter<T>;
• updateFilter: UpdateFilter<T>;
• readConfig: ReadConfig;
• updateOptions: UpdateOptions;

Returns Promise<UpdateResult>.

atomic.updateMany

updateMany: (
  filter: Filter<T>,
  updateFilter: UpdateFilter<T>,
  readConfig: ReadConfig = {},
  updateOptions: UpdateOptions = {},
): Promise<Document | UpdateResult>

await userService.atomic.updateMany(
  { firstName: { $exists: true }, lastName: { $exists: true } },
  { $set: { fullName: `${u.firstName} ${u.lastName}` } }
);

Updates all documents that match the specified filter. Doesn't validate schema or publish events.

Parameters

• filter: Filter<T>;
• updateFilter: UpdateFilter<T>;
• readConfig: ReadConfig;
• updateOptions: UpdateOptions;

Returns Promise<UpdateResult | Document>.

exists

exists(
  filter: Filter<T>,
  readConfig: ReadConfig = {},
  findOptions: FindOptions = {},
): Promise<boolean>

const isUserExists = await userService.exists({ email: "[e-mail]" });

Returns true if document exists, otherwise false.

Parameters

• filter: Filter<T>;
• readConfig: ReadConfig;
• findOptions: FindOptions;

Returns Promise<boolean>.

countDocuments

countDocuments(
  filter: Filter<T>,
  readConfig: ReadConfig = {},
  countDocumentOptions: CountDocumentsOptions = {},
): Promise<boolean>

const documentsCount = await userService.countDocuments({ status: "active" });

Returns amount of documents that matches the query.

Parameters

• filter: Filter<T>;
• readConfig: ReadConfig;
• countDocumentOptions: CountDocumentsOptions;

Returns Promise<number>.

distinct

distinct(
  key: string,
  filter: Filter<T>,
  readConfig: ReadConfig = {},
  distinctOptions: DistinctOptions = {},
): Promise<any[]>

const statesList = await userService.distinct("states");

Returns distinct values for a specified field across a single collection or view and returns the results in an array.

Parameters

• key: string;
• filter: Filter<T>;
• readConfig: ReadConfig;
• distinctOptions: DistinctOptions;

Returns Promise<any[]>.

aggregate

aggregate: (
  pipeline: any[],
  options: AggregateOptions = {},
): Promise<any[]>

const sortedActiveUsers = await userService.aggregate([
  { $match: { status: "active" } },
  { $sort: { firstName: -1, lastName: -1 } },
]);

Executes an aggregation framework pipeline and returns array with aggregation result of documents.

Parameters

• pipeline: any[];
• options: AggregateOptions;

Returns Promise<any[]>.

watch

watch: (
  pipeline: Document[] | undefined,
  options: ChangeStreamOptions = {},
): Promise<any>

const watchCursor = userService.watch();

Creates a new Change Stream, watching for new changes and returns a cursor.

Parameters

• pipeline: Document[] | undefined;
• options: ChangeStreamOptions;

Returns Promise<any>.

drop

drop: (
  recreate: boolean = false,
): Promise<void>

await userService.drop();

Removes a collection from the database. The method also removes any indexes associated with the dropped collection.

Parameters

• recreate: boolean; Should create collection after deletion.

Returns Promise<void>.

indexExists

indexExists: (
  indexes: string | string[],
  indexInformationOptions: IndexInformationOptions = {},
): Promise<boolean>

const isIndexExists = await usersService.indexExists(index);

Checks if one or more indexes exist on the collection, fails on first non-existing index.

Parameters

• indexes: string | string[];
• indexInformationOptions: IndexInformationOptions;

Returns Promise<string | void>.

createIndex

createIndex: (
  indexSpec: IndexSpecification,
  options: CreateIndexesOptions = {},
): Promise<string | void>

await usersService.createIndex({ fullName: 1 });

Creates collection index.

Parameters

• indexSpec: IndexSpecification;
• options: CreateIndexesOptions;

Returns Promise<string | void>.

createIndexes

createIndexes: (
  indexSpecs: IndexDescription[],
  options: CreateIndexesOptions = {},
): Promise<string[] | void>

await usersService.createIndexes([
  { key: { fullName: 1 } },
  { key: { createdOn: 1 } },
]);

Creates one or more indexes on a collection.

Parameters

• indexSpecs: IndexDescription[];
• options: CreateIndexesOptions;

Returns Promise<string[] | void>.

dropIndex

dropIndex: (
  indexName: string,
  options: DropIndexesOptions = {},
): Promise<void | Document>

await userService.dropIndex({ firstName: 1, lastName: -1 });

Removes the specified index from a collection.

Parameters

• indexName: string;
• options: DropIndexesOptions;

Returns Promise<void | Document>.

dropIndexes

dropIndexes: (
  options: DropIndexesOptions = {},
): Promise<void | Document>

Removes all but the _id index from a collection.

await userService.dropIndexes();

Parameters

• options: DropIndexesOptions;

Returns Promise<void | Document>.

Events API

eventBus.on

on: (
  eventName: string,
  handler: InMemoryEventHandler,
): void

import { eventBus, InMemoryEvent } from "@paralect/node-mongo";

const collectionName = "users";

eventBus.on(`${collectionName}.created`, (data: InMemoryEvent<User>) => {
  try {
    const user = data.doc;

    console.log("user created", user);
  } catch (err) {
    logger.error(`${USERS}.created handler error: ${err}`);
  }
});

eventBus.on(`${collectionName}.updated`, (data: InMemoryEvent<User>) => {});

eventBus.on(`${collectionName}.deleted`, (data: InMemoryEvent<User>) => {});

In-memory events handler that listens for a CUD events.

Parameters

• eventName: string;
  Events names to listen.
  Valid format: ${collectionName}.created, ${collectionName}.updated, ${collectionName}.deleted.
• handler: InMemoryEventHandler;

Returns void.

eventBus.once

once: (
  eventName: string,
  handler: InMemoryEventHandler,
): void

eventBus.once(`${USERS}.updated`, (data: InMemoryEvent<User>) => {
  try {
    const user = data.doc;

    console.log("user updated", user);
  } catch (err) {
    logger.error(`${USERS}.updated handler error: ${err}`);
  }
});

In-memory events handler that listens for a CUD events. It will be called only once.

Parameters

• eventName: string;
  Events names to listen.
  Valid format: ${collectionName}.created, ${collectionName}.updated, ${collectionName}.deleted.
• handler: InMemoryEventHandler;

Returns void.

eventBus.onUpdated

onUpdated: (
  entity: string,
  properties: OnUpdatedProperties,
  handler: InMemoryEventHandler,
): void

import { eventBus, InMemoryEvent } from "@paralect/node-mongo";

eventBus.onUpdated(
  "users",
  ["firstName", "lastName"],
  async (data: InMemoryEvent<User>) => {
    try {
      await userService.atomic.updateOne(
        { _id: data.doc._id },
        { $set: { fullName: `${data.doc.firstName} ${data.doc.lastName}` } }
      );
    } catch (err) {
      console.log(
        `users onUpdated ['firstName', 'lastName'] handler error: ${err}`
      );
    }
  }
);

eventBus.onUpdated(
  "users",
  [{ fullName: "John Wake", firstName: "John" }, "lastName"],
  () => {}
);

eventBus.onUpdated("users", ["oauth.google"], () => {});

In-memory events handler that listens for specific fields updates. It will be called when one of the provided properties updates.

Parameters

• entity: string;
  Collection name for events listening.
• properties: OnUpdatedProperties;
  Properties whose update will trigger the event.
• handler: InMemoryEventHandler;

Returns void.

Transactions API

withTransaction

withTransaction: <TRes = any>(
  transactionFn: (session: ClientSession) => Promise<TRes>,
): Promise<TRes>

Runs callbacks and automatically commits or rollbacks transaction.

import db from "db";

const { user, company } = await db.withTransaction(async (session) => {
  const createdUser = await usersService.insertOne(
    { fullName: "Bahrimchuk" },
    {},
    { session }
  );
  const createdCompany = await companyService.insertOne(
    { users: [createdUser._id] },
    {},
    { session }
  );

  return { user: createdUser, company: createdCompany };
});

Parameters

• transactionFn: (session: ClientSession) => Promise<TRes>;
  Function that accepts a client session and manages some business logic. Must return a Promise.

Returns Promise<TRes>.

Options and Types

ServiceOptions

interface ServiceOptions {
  skipDeletedOnDocs?: boolean;
  schemaValidator?: (obj: any) => Promise<any>;
  publishEvents?: boolean;
  addCreatedOnField?: boolean;
  addUpdatedOnField?: boolean;
  outbox?: boolean;
  collectionOptions?: CollectionOptions;
  collectionCreateOptions?: CreateCollectionOptions;
}

Option	Description	Default value
skipDeletedOnDocs	Skip documents with the deletedOn field	true
schemaValidator	Validation function that will be called on data save	-
publishEvents	Publish CUD events on save.	true
addCreatedOnField	Set the createdOn field to the current timestamp on document creation.	true
addUpdatedOnField	Set updateOne field to the current timestamp on the document update.	true
outbox	Use transactional events instead of in-memory events	false
collectionOptions	MongoDB CollectionOptions	{}
collectionCreateOptions	MongoDB CreateCollectionOptions	{}

CreateConfig

Overrides ServiceOptions parameters for create operations.

type CreateConfig = {
  validateSchema?: boolean;
  publishEvents?: boolean;
};

ReadConfig

Overrides ServiceOptions parameters for read operations.

type ReadConfig = {
  skipDeletedOnDocs?: boolean;
};

UpdateConfig

Overrides ServiceOptions parameters for update operations.

type UpdateConfig = {
  skipDeletedOnDocs?: boolean;
  validateSchema?: boolean;
  publishEvents?: boolean;
};

DeleteConfig

Overrides ServiceOptions parameters for delete operations.

type DeleteConfig = {
  skipDeletedOnDocs?: boolean;
  publishEvents?: boolean;
};

InMemoryEvent

type InMemoryEvent<T = any> = {
  doc: T;
  prevDoc?: T;
  name: string;
  createdOn: Date;
};

InMemoryEventHandler

type InMemoryEventHandler = (evt: InMemoryEvent) => Promise<void> | void;

OnUpdatedProperties

type OnUpdatedProperties = Array<Record<string, unknown> | string>;

Extending API

Extending API for a single service.

const service = db.createService<User>("users", {
  schemaValidator: (obj) => schema.parseAsync(obj),
});

const privateFields = ["passwordHash", "signupToken", "resetPasswordToken"];

const getPublic = (user: User | null) => _.omit(user, privateFields);

export default Object.assign(service, {
  updateLastRequest,
  getPublic,
});

Extending API for all services.

const database = new Database(config.mongo.connection, config.mongo.dbName);

class CustomService<T extends IDocument> extends Service<T> {
  createOrUpdate = async (
    query: any,
    updateCallback: (item?: T) => Partial<T>
  ) => {
    const docExists = await this.exists(query);

    if (!docExists) {
      const newDoc = updateCallback();
      return this.insertOne(newDoc);
    }

    return this.updateOne(query, (doc) => updateCallback(doc));
  };
}

function createService<T extends IDocument>(
  collectionName: string,
  options: ServiceOptions = {}
) {
  return new CustomService<T>(collectionName, database, options);
}

const userService = createService<UserType>("users", {
  schemaValidator: (obj) => schema.parseAsync(obj),
});

await userService.createOrUpdate({ _id: "some-id" }, () => ({
  fullName: "Max",
}));