### Quick start example

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/docs/guide/core.md

A basic example demonstrating how to initialize the YDB driver and wait for it to be ready.

```typescript
import { Driver } from '@ydbjs/core'

const driver = new Driver(process.env['YDB_CONNECTION_STRING'] || 'grpc://localhost:2136/local')
await driver.ready()

// use the driver with Query/Topic or low-level clients

await driver.close()
```

--------------------------------

### Setup

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/examples/coordination/README.md

Installs dependencies, builds packages, and navigates to the coordination examples directory. Also shows how to set the YDB connection string.

```bash
# From the repository root
npm install
npm run build

cd examples/coordination
```

```bash
export YDB_CONNECTION_STRING=grpc://localhost:2136/local
```

--------------------------------

### Runnable Examples

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/docs/guide/drizzle/getting-started.md

Instructions to run the compact TypeScript CLI example from the SDK repository.

```bash
cd examples/drizzle-adapter
npm install
npm start
```

--------------------------------

### Run the example

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/examples/diagnostics/README.md

Install dependencies and start the example with a default connection string.

```sh
npm install
YDB_CONNECTION_STRING=grpc://localhost:2136/local npm start
```

--------------------------------

### Query Example Setup

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/examples/README.MD

Setup instructions for the SQL queries example.

```bash
cd examples/query
npm install && npm start
```

--------------------------------

### Serverless Example Setup

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/examples/README.MD

Setup instructions for the serverless considerations example.

```bash
cd examples/sls
npm install && npm start
```

--------------------------------

### API Example Setup

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/examples/README.MD

Setup instructions for the low-level API usage example.

```bash
cd examples/api
npm install && npm start
```

--------------------------------

### Install

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/docs/guide/drizzle/getting-started.md

Install the Drizzle adapter and drizzle-orm using npm.

```sh
npm install @ydbjs/drizzle-adapter drizzle-orm
```

--------------------------------

### Getting Started: Using direct factories

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/packages/topic/README.md

Example demonstrating how to use direct factory functions for creating readers and writers.

```ts
import { Driver } from '@ydbjs/core'
import { createTopicReader, createTopicTxReader } from '@ydbjs/topic/reader'
import { createTopicWriter, createTopicTxWriter } from '@ydbjs/topic/writer'

const driver = new Driver(process.env['YDB_CONNECTION_STRING']!)
await driver.ready()

await using reader = createTopicReader(driver, {
  topic: '/Root/my-topic',
  consumer: 'my-consumer',
})
await using writer = createTopicWriter(driver, {
  topic: '/Root/my-topic',
  producer: 'my-producer',
})
```

--------------------------------

### FSM Example Setup

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/examples/README.MD

Setup instructions for the FSM runtime usage example.

```bash
cd examples/fsm
npm install && npm start
```

--------------------------------

### Running the example

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/examples/fsm/README.md

Commands to navigate to the example directory, install dependencies, and run the example.

```bash
cd examples/fsm
npm install
npm start
```

--------------------------------

### Getting Started: Using the top-level client

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/packages/topic/README.md

Example demonstrating how to create and use a reader and writer with the top-level topic client.

```ts
import { Driver } from '@ydbjs/core'
import { topic } from '@ydbjs/topic'

const driver = new Driver(process.env['YDB_CONNECTION_STRING']!)
await driver.ready()

const t = topic(driver)

// Reader
await using reader = t.createReader({
  topic: '/Root/my-topic',
  consumer: 'my-consumer',
})
for await (const batch of reader.read()) {
  // Process messages
  for (const msg of batch) console.log(new TextDecoder().decode(msg.payload))
  // Commit processed offsets (see performance note below)
  await reader.commit(batch)
}

// Writer
await using writer = t.createWriter({
  topic: '/Root/my-topic',
  producer: 'my-producer',
})
writer.write(new TextEncoder().encode('Hello, YDB!'))
await writer.flush()
```

--------------------------------

### Topic Example Setup

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/examples/README.MD

Setup instructions for the Topic reader/writer and transactional usage example.

```bash
cd examples/topic
npm install && npm start
```

--------------------------------

### Service Account Example Setup

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/examples/README.MD

Setup instructions for the Yandex Cloud Service Account authentication example.

```bash
cd examples/service-account
npm install && npm start
```

--------------------------------

### Low-level Service Client Example

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/docs/guide/core.md

Example of creating and using a low-level service client, specifically for the DiscoveryService.

```typescript
import { DiscoveryServiceDefinition } from '@ydbjs/api/discovery'

const discovery = driver.createClient(DiscoveryServiceDefinition)
const endpoints = await discovery.listEndpoints({ database: driver.database })
```

--------------------------------

### TLS Example Setup

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/examples/README.MD

Setup instructions for the TLS with custom CA, mTLS example.

```bash
cd examples/tls
npm install && npm start
```

--------------------------------

### Telemetry Example Setup

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/examples/README.MD

Setup instructions for the OpenTelemetry tracing + metrics example.

```bash
cd examples/telemetry
npm install && npm start
```

--------------------------------

### Drizzle Adapter Example Setup

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/examples/README.MD

Setup instructions for the Drizzle ORM adapter example.

```bash
cd examples/drizzle-adapter
npm install && npm start
```

--------------------------------

### Coordination Example Setup

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/examples/README.MD

Setup instructions for the Coordination nodes, distributed semaphores, leader election example.

```bash
cd examples/coordination
npm install && npm start
```

--------------------------------

### Quick Setup for AI Assistants

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/packages/query/SECURITY.md

Copies example AI instruction files to the project root for different AI assistants.

```bash
# For Cursor users
cp node_modules/@ydbjs/query/ai-instructions/.cursorrules.example .cursorrules

# For GitHub Copilot users
cp node_modules/@ydbjs/query/ai-instructions/.copilot-instructions.example.md .copilot-instructions.md

# For general AI assistants
cp node_modules/@ydbjs/query/ai-instructions/.instructions.example.md .instructions.md
# OR
cp node_modules/@ydbjs/query/ai-instructions/.ai-instructions.example.md .ai-instructions.md
```

--------------------------------

### Quick Setup Commands

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/packages/query/ai-instructions/README.md

Commands to copy example AI instruction files to the project root for different AI assistants.

```bash
cp node_modules/@ydbjs/query/ai-instructions/.cursorrules.example .cursorrules

# For GitHub Copilot
cp node_modules/@ydbjs/query/ai-instructions/.copilot-instructions.example.md .copilot-instructions.md

# For general AI assistants
cp node_modules/@ydbjs/query/ai-instructions/.instructions.example.md .instructions.md
# OR
cp node_modules/@ydbjs/query/ai-instructions/.ai-instructions.example.md .ai-instructions.md
```

--------------------------------

### Quick Setup for AI Assistant Configuration

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/packages/query/README.md

Commands to copy example AI assistant configuration files to the project root.

```bash
# Choose the appropriate file for your AI assistant
cp node_modules/@ydbjs/query/ai-instructions/.cursorrules.example .cursorrules
cp node_modules/@ydbjs/query/ai-instructions/.instructions.example.md .instructions.md
```

--------------------------------

### Environment-Based Auto-Detection

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/docs/guide/core.md

Example demonstrating the use of EnvironCredentialsProvider for automatic authentication strategy detection.

```typescript
import { Driver } from '@ydbjs/core'
import { EnvironCredentialsProvider } from '@ydbjs/auth/environ'

let cs = process.env['YDB_CONNECTION_STRING']!
let creds = new EnvironCredentialsProvider(cs)

const driver = new Driver(cs, {
  credentialsProvider: creds,
  secureOptions: creds.secureOptions,
})
await driver.ready()
```

--------------------------------

### Setup

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/CONTRIBUTING.md

Clones the repository and installs dependencies.

```bash
git clone https://github.com/ydb-platform/ydb-js-sdk.git
cd ydb-js-sdk
npm ci
```

--------------------------------

### Quick Start

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/packages/fsm/README.md

A basic example demonstrating the creation and usage of a finite state machine runtime with typed states, events, effects, and outputs.

```ts
import { createMachineRuntime } from '@ydbjs/fsm'

type State = 'idle' | 'running' | 'done'
type Event =
  | { type: 'counter.start' }
  | { type: 'counter.increment'; step?: number }
  | { type: 'counter.finish' }

type Effect = { type: 'counter.log'; message: string }
type Output = { type: 'counter.state'; value: State } | { type: 'counter.value'; value: number }

type Context = { count: number }

let runtime = createMachineRuntime<State, Context, Event, Effect, Output>({
  initialState: 'idle',
  context: { count: 0 },
  transition(context, state, event, runtime) {
    switch (event.type) {
      case 'counter.start':
        runtime.emit({ type: 'counter.state', value: 'running' })
        return { state: 'running', effects: [{ type: 'counter.log', message: 'started' }] }

      case 'counter.increment':
        if (state !== 'running') return
        context.count += event.step ?? 1
        runtime.emit({ type: 'counter.value', value: context.count })
        return { effects: [{ type: 'counter.log', message: `count=${context.count}` }] }

      case 'counter.finish':
        runtime.emit({ type: 'counter.state', value: 'done' })
        return { state: 'done', effects: [{ type: 'counter.log', message: 'finished' }] }
    }
  },
  effects: {
    'counter.log'(effect) {
      console.log('[effect]', effect.message)
    },
  },
})

void (async () => {
  for await (let out of runtime) {
    console.log(out)
  }
})()

runtime.dispatch({ type: 'counter.start' })
runtime.dispatch({ type: 'counter.increment' })
runtime.dispatch({ type: 'counter.finish' })

await runtime.close('done')
await runtime.destroy('finalized')

```

--------------------------------

### Static Credentials Authentication

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/docs/guide/core.md

Example of configuring the driver with static username and password credentials.

```typescript
import { Driver } from '@ydbjs/core'
import { StaticCredentialsProvider } from '@ydbjs/auth/static'

const authEndpoint = 'grpcs://ydb.example.com:2135' // AuthService endpoint
const driver = new Driver('grpcs://ydb.example.com:2135/your-db', {
  credentialsProvider: new StaticCredentialsProvider(
    {
      username: process.env.YDB_USER!,
      password: process.env.YDB_PASSWORD!,
    },
    authEndpoint
  ),
})
await driver.ready()
```

--------------------------------

### Run All Examples

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/examples/README.MD

Commands to run all the provided examples.

```bash
cd examples/api && npm start
cd examples/query && npm run dev
cd examples/drizzle-adapter && npm start
cd examples/sls && npm start
cd examples/tls && npm start
cd examples/topic && npm start
cd examples/coordination && npm start
cd examples/fsm && npm start
cd examples/telemetry && npm start
cd examples/service-account && npm start
```

--------------------------------

### Quick Start

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/third-parties/drizzle-adapter/README.md

A quick start example demonstrating how to use the @ydbjs/drizzle-adapter to insert and select data.

```ts
import { eq } from 'drizzle-orm'
import { createDrizzle } from '@ydbjs/drizzle-adapter'
import {
  integer,
  primaryKey,
  text,
  timestamp,
  uint64,
  ydbTable,
} from '@ydbjs/drizzle-adapter/schema'
import { currentUtcTimestamp, numericHash } from '@ydbjs/drizzle-adapter/sql'

let users = ydbTable(
  'users',
  {
    hash: uint64('hash').notNull(),
    id: integer('id').notNull(),
    email: text('email').notNull(),
    createdAt: timestamp('created_at').notNull(),
  },
  (t) => [primaryKey(t.hash, t.id)]
)

let db = createDrizzle({
  connectionString: process.env['YDB_CONNECTION_STRING']!,
  schema: { users },
})

await db
  .insert(users)
  .values({
    hash: numericHash(1),
    id: 1,
    email: 'ada@example.com',
    createdAt: currentUtcTimestamp(),
  })
  .execute()

let row = await db
  .select({ id: users.id, email: users.email })
  .from(users)
  .where(eq(users.id, 1))
  .prepare()
  .get()

await db.$client.close?.()
```

--------------------------------

### Quick Start

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/docs/guide/drizzle/index.md

A quick start example demonstrating basic Drizzle operations with the YDB adapter, including schema definition, insertion, querying, and selection.

```typescript
import { createDrizzle } from '@ydbjs/drizzle-adapter'
import { integer, text, ydbTable } from '@ydbjs/drizzle-adapter/schema'
import { eq } from 'drizzle-orm'

export const users = ydbTable('users', {
  id: integer('id').primaryKey(),
  name: text('name').notNull(),
})

const db = createDrizzle({
  connectionString: process.env.YDB_CONNECTION_STRING!,
  schema: { users },
})

await db.insert(users).values({ id: 1, name: 'Alice' }).execute()

const row = await db.query.users.findFirst({
  where: (user, { eq }) => eq(user.id, 1),
})

const selected = await db
  .select({ id: users.id, name: users.name })
  .from(users)
  .where(eq(users.id, 1))
  .prepare()
  .get()
```

--------------------------------

### Access Token Authentication

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/docs/guide/core.md

Example of configuring the driver with an Access Token credentials provider.

```typescript
import { Driver } from '@ydbjs/core'
import { AccessTokenCredentialsProvider } from '@ydbjs/auth/access-token'

const driver = new Driver('grpcs://ydb.example.com:2135/your-db', {
  credentialsProvider: new AccessTokenCredentialsProvider({
    token: process.env.YDB_TOKEN!,
  }),
})
await driver.ready()
```

--------------------------------

### Run with discovery enabled

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/examples/diagnostics/README.md

Start a local YDB container with discovery enabled and run the example.

```sh
docker run -d --rm --name ydb-diag-demo --hostname localhost \
  -p 2136:2136 ydbplatform/local-ydb:latest

ENABLE_DISCOVERY=1 \
  YDB_CONNECTION_STRING=grpc://localhost:2136/local \
  npm start
```

--------------------------------

### Quick start

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/docs/guide/coordination/index.md

This example demonstrates how to create a coordination node, acquire an exclusive lock using a mutex, and perform work.

```typescript
import { Driver } from '@ydbjs/core'
import { CoordinationClient } from '@ydbjs/coordination'

const driver = new Driver(process.env['YDB_CONNECTION_STRING']!)
const client = new CoordinationClient(driver)

// Create a coordination node once during provisioning
await client.createNode('/local/my-app', {})

// Acquire an exclusive lock
await using session = await client.createSession('/local/my-app', {})
await using lock = await session.mutex('job-lock').lock()

await doWork(lock.signal)
// lock.release()  ← called automatically
// session.close() ← called automatically
```

--------------------------------

### Quick Start

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/docs/guide/query/index.md

This is a basic example of how to use the @ydbjs/query client to execute a simple YQL query.

```typescript
import { Driver } from '@ydbjs/core'
import { query } from '@ydbjs/query'

const driver = new Driver('grpc://localhost:2136/local')
await driver.ready()

const sql = query(driver)
const rows = await sql`SELECT 1 + 1 AS sum`
console.log(rows)
```

--------------------------------

### YDB Local Docker Run

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/examples/README.MD

Command to start a local YDB instance using Docker.

```bash
docker run -d --rm --name ydb-local -h localhost \
  --platform linux/amd64 \
  -p 2135:2135 -p 2136:2136 -p 8765:8765 -p 9092:9092 \
  -e GRPC_TLS_PORT=2135 -e GRPC_PORT=2136 -e MON_PORT=8765 \
  -e YDB_KAFKA_PROXY_PORT=9092 \
  ydbplatform/local-ydb:latest
```

--------------------------------

### Service Discovery — service-discovery.js

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/examples/coordination/README.md

Runs the service discovery example.

```bash
npm run service-discovery
```

--------------------------------

### Run the example

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/examples/telemetry/README.md

Command-line instructions to run the YDB OpenTelemetry example, with options for default and custom connection strings and OTLP endpoints.

```bash
# Defaults to grpc://localhost:2136/local and OTLP http://localhost:4318.
node index.js

# Or point at a real collector / cluster:
YDB_CONNECTION_STRING=grpcs://your.host:2135/?database=/ru/your/database \
OTEL_EXPORTER_OTLP_ENDPOINT=http://collector.local:4318 \
  node index.js
```

--------------------------------

### Usage Examples

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/examples/environ/README.md

Demonstrates how to set environment variables for different authentication methods.

```bash
# Anonymous (local YDB)
YDB_CONNECTION_STRING=grpc://localhost:2136/local npm start
```

```bash
# Static credentials (on-premises)
YDB_CONNECTION_STRING=grpcs://ydb.example.com:2135/mydb \
YDB_STATIC_CREDENTIALS_USER=admin \
YDB_STATIC_CREDENTIALS_PASSWORD=secret \
YDB_SSL_ROOT_CERTIFICATES_FILE=/path/to/ca.pem \
npm start
```

```bash
# Access token
YDB_CONNECTION_STRING=grpcs://ydb.example.com:2135/mydb \
YDB_ACCESS_TOKEN_CREDENTIALS=my-token \
npm start
```

```bash
# Metadata (cloud VM)
YDB_CONNECTION_STRING=grpcs://ydb.example.com:2135/mydb \
YDB_METADATA_CREDENTIALS=1 \
npm start
```

--------------------------------

### Shared Configuration — shared-config.js

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/examples/coordination/README.md

Runs the shared configuration example.

```bash
npm run shared-config
```

--------------------------------

### Installation

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/packages/auth/README.md

Install the package using npm.

```sh
npm install @ydbjs/auth
```

--------------------------------

### Installation

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/packages/core/README.md

Install the @ydbjs/core package using npm.

```sh
npm install @ydbjs/core
```

--------------------------------

### Leader Election — election.js

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/examples/coordination/README.md

Runs the leader election example.

```bash
npm run election
```

--------------------------------

### YDB Connection String Environment Variable

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/examples/README.MD

Environment variable to set the YDB connection string for manual setup.

```bash
export YDB_CONNECTION_STRING="grpc://localhost:2136/local"
```

--------------------------------

### Example: Using a Service

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/packages/api/README.md

An example demonstrating how to use the DiscoveryService with nice-grpc to list endpoints.

```ts
import { createClientFactory, createChannel } from 'nice-grpc'
import { DiscoveryServiceDefinition } from '@ydbjs/api/discovery'

const clientFactory = createClientFactory()
const discoveryClient = clientFactory.create(
  DiscoveryServiceDefinition,
  createChannel('http://localhost:2136')
)

async function listEndpoints() {
  const response = await discoveryClient.listEndpoints({ database: '/local' })
  console.log(response)
}

listEndpoints().catch(console.error)
```

--------------------------------

### Installation

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/packages/coordination/README.md

Install the @ydbjs/coordination package using npm.

```bash
npm install @ydbjs/coordination
```

--------------------------------

### Installation

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/packages/value/README.md

Install the package using npm.

```sh
npm install @ydbjs/value
```

--------------------------------

### Installation

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/packages/api/README.md

Install the @ydbjs/api package using npm.

```sh
npm install @ydbjs/api
```

--------------------------------

### Installation

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/packages/topic/README.md

Install the @ydbjs/topic package using npm.

```sh
npm install @ydbjs/topic
```

--------------------------------

### Installation

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/packages/fsm/README.md

Install the @ydbjs/fsm package using npm.

```sh
npm install @ydbjs/fsm
```

--------------------------------

### Distributed Mutex — mutex.js

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/examples/coordination/README.md

Runs the distributed mutex example.

```bash
npm run mutex
```

--------------------------------

### TLS/mTLS with StaticCredentialsProvider

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/docs/guide/core.md

Example of using StaticCredentialsProvider with TLS/mTLS options for authentication against AuthService.

```typescript
import { Driver } from '@ydbjs/core'
import { StaticCredentialsProvider } from '@ydbjs/auth/static'
import * as fs from 'node:fs'

const authEndpoint = 'grpcs://ydb.example.com:2135'
const driver = new Driver('grpcs://ydb.example.com:2135/your-db', {
  credentialsProvider: new StaticCredentialsProvider(
    {
      username: 'user',
      password: 'pass',
    },
    authEndpoint,
    {
      ca: fs.readFileSync('/etc/ssl/custom/ca.pem'),
      cert: fs.readFileSync('/etc/ssl/custom/client.crt'), // for mTLS
      key: fs.readFileSync('/etc/ssl/custom/client.key'), // for mTLS
    }
  ),
})
await driver.ready()
```

--------------------------------

### Basic Example

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/packages/core/README.md

A basic example demonstrating how to initialize the driver, create a client for the Discovery service, list endpoints, and close the driver.

```ts
import { Driver } from '@ydbjs/core'
import { DiscoveryServiceDefinition } from '@ydbjs/api/discovery'

const driver = new Driver('grpc://localhost:2136/local')
await driver.ready()

const discovery = driver.createClient(DiscoveryServiceDefinition)
const endpoints = await discovery.listEndpoints({ database: '/local' })
console.log(endpoints)

await driver.close()
```

--------------------------------

### TLS with custom CA

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/docs/guide/core.md

Example of configuring TLS with a custom Certificate Authority (CA) file.

```typescript
import { Driver } from '@ydbjs/core'
import * as fs from 'node:fs'

const driver = new Driver('grpcs://ydb.example.com:2135/your-db', {
  secureOptions: {
    ca: fs.readFileSync('/etc/ssl/custom/ca.pem'),
    servername: 'ydb.example.com', // SNI if needed
  },
})
await driver.ready()
```

--------------------------------

### Anonymous Authentication

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/docs/guide/core.md

Example of configuring the driver for anonymous access, suitable for local or public databases.

```typescript
import { Driver } from '@ydbjs/core'
import { AnonymousCredentialsProvider } from '@ydbjs/auth/anonymous'

const driver = new Driver('grpc://localhost:2136/local', {
  credentialsProvider: new AnonymousCredentialsProvider(),
})
await driver.ready()
```

--------------------------------

### Metadata Authentication

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/docs/guide/core.md

Example of configuring the driver with metadata credentials, typically used in cloud environments.

```typescript
import { Driver } from '@ydbjs/core'
import { MetadataCredentialsProvider } from '@ydbjs/auth/metadata'

const driver = new Driver(process.env.YDB_CONNECTION_STRING!, {
  credentialsProvider: new MetadataCredentialsProvider({
    // endpoint?: 'http://169.254.169.254/computeMetadata/v1/instance/service-accounts/default/token'
  }),
})
await driver.ready()
```

--------------------------------

### mTLS (client cert + key)

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/docs/guide/core.md

Example of configuring mutual TLS (mTLS) with client certificates and keys.

```typescript
import { Driver } from '@ydbjs/core'
import * as fs from 'node:fs'

const driver = new Driver('grpcs://ydb.example.com:2135/your-db', {
  secureOptions: {
    ca: fs.readFileSync('/etc/ssl/custom/ca.pem'),
    cert: fs.readFileSync('/etc/ssl/custom/client.crt'),
    key: fs.readFileSync('/etc/ssl/custom/client.key'),
    // passphrase?: '...',
  },
})
await driver.ready()
```

--------------------------------

### Custom CredentialsProvider with AbortSignal Handling

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/docs/guide/core.md

Example of a custom CredentialsProvider that correctly handles AbortSignal for network requests and timeouts.

```typescript
class MyCredentialsProvider extends CredentialsProvider {
  #token: string | null = null

  async getToken(force = false, signal: AbortSignal = AbortSignal.timeout(10_000)) {
    if (!force && this.#token) return this.#token
    const abort = AbortSignal.any([signal, AbortSignal.timeout(15_000)])
    const res = await fetch(this.#endpoint, {
      method: 'POST',
      body: '{}',
      signal: abort,
    })
    if (!res.ok) throw new Error(`Auth failed: ${res.status}`)
    const { token } = await res.json()
    this.#token = token
    return token
  }
}
```

--------------------------------

### Custom CredentialsProvider Implementation

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/docs/guide/core.md

Example of implementing a custom CredentialsProvider by extending the base class and overriding the getToken method.

```typescript
import { CredentialsProvider } from '@ydbjs/auth'

class MyCredentialsProvider extends CredentialsProvider {
  #token: string | null = null
  async getToken(force = false, signal?: AbortSignal): Promise<string> {
    if (!force && this.#token) return this.#token
    const token = await fetchTokenSomehow(signal)
    this.#token = token
    return token
  }
}

const driver = new Driver(process.env.YDB_CONNECTION_STRING!, {
  credentialsProvider: new MyCredentialsProvider(),
})
```

--------------------------------

### Resource Management with await using — resource-management.js

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/examples/coordination/README.md

Runs the resource management example using await using.

```bash
npm run resource-management
```

--------------------------------

### Quick start

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/docs/guide/topic/index.md

This code snippet demonstrates how to initialize the YDB driver and create a topic reader to consume messages.

```typescript
import { Driver } from '@ydbjs/core'
import { topic } from '@ydbjs/topic'

const driver = new Driver(process.env['YDB_CONNECTION_STRING']!)
await driver.ready()

const t = topic(driver)
await using reader = t.createReader({ topic: '/Root/my-topic', consumer: 'c1' })
for await (const batch of reader.read()) {
  await reader.commit(batch)
}
```

--------------------------------

### Execution Methods Examples

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/docs/guide/drizzle/database-api.md

Examples of using execution methods like execute, all, get, and values with raw SQL and query builders.

```typescript
import { sql } from 'drizzle-orm'

await db.execute(sql`DELETE FROM users WHERE id = ${1}`)

const rows = await db.all(sql`SELECT * FROM users`)
const first = await db.get(sql`SELECT * FROM users LIMIT 1`)
const values = await db.values<[number, string]>(sql`SELECT id, name FROM users`)

const firstBuilt = await db.get(db.select({ id: users.id, name: users.name }).from(users).limit(1))
```

--------------------------------

### Partition session hooks

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/docs/guide/topic/index.md

This example shows how to use partition session hooks to manage read offsets and observe session start/stop events.

```typescript
await using reader = t.createReader({
  topic: '/Root/metrics',
  consumer: 'svc-a',
  onPartitionSessionStart: async (session, committed, { start, end }) => {
    // shift readOffset to resume from the last committed
    return { readOffset: committed }
  },
  onPartitionSessionStop: async (session, committed) => {
    console.log('partition closed', session.partitionSessionId, 'committed', committed)
  },
  onCommittedOffset: (session, committed) => {
    // observe commits (useful with fire-and-forget commit())
    console.log('committed', session.partitionSessionId, committed)
  },
})

```

--------------------------------

### Static Credentials (Manual Usage)

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/packages/auth/README.md

Example of manually using the StaticCredentialsProvider to get a token.

```ts
import { StaticCredentialsProvider } from '@ydbjs/auth/static'

const provider = new StaticCredentialsProvider(
  {
    username: 'username',
    password: 'password',
  },
  'grpc://localhost:2136/local'
)

const token = await provider.getToken()
// The token can be used in custom gRPC calls if needed
```

--------------------------------

### Open Session Example

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/docs/guide/coordination/index.md

This example shows how to use `openSession` for long-running work, with automatic session recreation after expiry.

```typescript
const ctrl = new AbortController()

for await (const session of client.openSession(
  '/local/my-app',
  { recoveryWindow: 15_000 },
  ctrl.signal
)) {
  try {
    await doWork(session)
  } catch {
    if (session.signal.aborted) continue // session expired — retry
    throw error
  }

  break // exit after one successful cycle
}
```

--------------------------------

### Shutdown

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/docs/guide/drizzle/getting-started.md

Close the adapter's owned client if it was created from a connection string.

```ts
db.$client.close?.()
```

--------------------------------

### Smoke Test

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/docs/guide/drizzle/getting-started.md

Execute a simple SQL query to test the database connection.

```ts
import { sql } from 'drizzle-orm'

await db.execute(sql`SELECT 1`)
```

--------------------------------

### Good Commit Message Examples

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/AGENTS.md

Examples of effective commit messages.

```bash
Add retry backoff strategy for transient errors

- Implement exponential backoff with jitter
- Add tests for retry behavior
- Update documentation
```

```bash
Fix memory leak in connection pool

- Close idle connections after timeout
- Add connection lifecycle tests
```

--------------------------------

### CRUD Operations

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/docs/guide/drizzle/getting-started.md

Basic Create, Read, Update, and Delete operations using the Drizzle adapter.

```ts
import { and, eq, like } from 'drizzle-orm'

await db.insert(users).values({ id: 1, email: 'alice@example.com', name: 'Alice' }).execute()

await db
  .insert(users)
  .values([
    { id: 2, email: 'bob@example.com', name: 'Bob' },
    { id: 3, email: 'charlie@example.com', name: 'Charlie' },
  ])
  .execute()

await db
  .insert(users)
  .values({ id: 1, email: 'alice_new@example.com', name: 'Alice Updated' })
  .onDuplicateKeyUpdate({ set: { name: 'Alice Updated' } })
  .execute()

const filteredUsers = await db
  .select({
    userId: users.id,
    userName: users.name,
  })
  .from(users)
  .where(and(eq(users.id, 1), like(users.email, '%@example.com')))
  .execute()

await db.update(users).set({ name: 'Alice Cooper' }).where(eq(users.id, 1)).execute()
await db.delete(users).where(eq(users.id, 1)).execute()
```

--------------------------------

### Parameters and AS_TABLE

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/docs/guide/query/index.md

Example demonstrating how to use parameters with the AS_TABLE function to insert data.

```typescript
const users = [
  { id: 1, name: 'Alice' },
  { id: 2, name: 'Bob' },
]
await sql`INSERT INTO users SELECT * FROM AS_TABLE(${users})`
```

--------------------------------

### Essential Development Commands

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/AGENTS.md

Lists key npm commands for building, testing, and linting the project.

```bash
npm run build           # Build all packages (Turbo)
npm run test:uni        # Unit tests (fast, no Docker)
npm run test:int        # Integration tests (requires Docker + YDB)
npm run test:all        # All tests (uni + int + e2e)
npm run lint            # Run oxlint
```

--------------------------------

### Basic reader/commit

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/docs/guide/topic/examples.md

Demonstrates how to create a topic reader, read batches of messages, and commit them.

```typescript
import { topic } from '@ydbjs/topic'

const t = topic(driver)
await using reader = t.createReader({ topic: '/Root/my-topic', consumer: 'c1' })

for await (const batch of reader.read({ limit: 100, waitMs: 1000 })) {
  if (!batch.length) continue
  // processing
  await reader.commit(batch)
}
```

--------------------------------

### Transactions

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/docs/guide/drizzle/getting-started.md

Perform database operations within a transaction, with options for access mode, isolation level, and idempotency.

```ts
import { TransactionRollbackError } from 'drizzle-orm/errors'

try {
  await db.transaction(
    async (tx) => {
      await tx.insert(users).values({ id: 4, email: 'delta@example.com' }).execute()

      const user = await tx.select().from(users).where(eq(users.id, 4)).execute()
      if (user.length === 0) {
        tx.rollback()
      }
    },
    {
      accessMode: 'read write',
      isolationLevel: 'serializableReadWrite',
      idempotent: true,
    }
  )
} catch (error) {
  if (error instanceof TransactionRollbackError) {
    console.log('transaction was rolled back')
  }
}
```

--------------------------------

### Multiple sources and partition filters

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/docs/guide/topic/index.md

This example demonstrates how to configure a topic reader to consume messages from multiple topics and filter by specific partition IDs.

```typescript
await using reader = t.createReader({
  topic: [{ path: '/Root/topic-a', partitionIds: [0n, 1n] }, { path: '/Root/topic-b' }],
  consumer: 'svc-a',
})

for await (const batch of reader.read({ waitMs: 500 })) {
  // process messages from both topics, filtered partitions
}
```

--------------------------------

### Define a Schema

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/docs/guide/drizzle/getting-started.md

Define a YDB table schema using adapter-specific builders. YDB tables require a primary key.

```ts
import { integer, text, timestamp, ydbTable } from '@ydbjs/drizzle-adapter/schema'

export const users = ydbTable('users', {
  id: integer('id').primaryKey(),
  email: text('email').notNull().unique(),
  name: text('name'),
  createdAt: timestamp('created_at')
    .notNull()
    .$defaultFn(() => new Date()),
})
```

--------------------------------

### Connect using Existing SDK Driver

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/docs/guide/drizzle/getting-started.md

Wrap an existing SDK Driver with YdbDriver when your application already owns the driver.

```ts
import { Driver } from '@ydbjs/core'
import { YdbDriver, createDrizzle } from '@ydbjs/drizzle-adapter'

const driver = new Driver('grpc://localhost:2136/local')
const db = createDrizzle({
  client: new YdbDriver(driver),
})
```

--------------------------------

### Custom codecs

Source: https://github.com/ydb-platform/ydb-js-sdk/blob/main/docs/guide/topic/examples.md

Illustrates how to implement and use custom codecs for topic messages, using GZIP as an example.

```typescript
import { Codec } from '@ydbjs/api/topic'
import * as zlib from 'node:zlib'

const MyGzip = {
  codec: Codec.GZIP,
  compress: (p: Uint8Array) => zlib.gzipSync(p),
  decompress: (p: Uint8Array) => zlib.gunzipSync(p),
}

await using reader = t.createReader({
  topic: '/Root/custom',
  consumer: 'c1',
  codecMap: new Map([[Codec.GZIP, MyGzip]]),
})
```