Features

Deep dive into Vestig's core features.

Structured Output

Vestig outputs logs as JSON by default in production, making them easy to parse and analyze with tools like Datadog, Splunk, or CloudWatch.

typescript

1import { log } from 'vestig'
2 
3log.info('User action', { userId: '123', action: 'click' })

Output:

json

1{
2  "level": "info",
3  "message": "User action",
4  "metadata": {
5    "userId": "123",
6    "action": "click"
7  },
8  "timestamp": "2024-01-15T10:30:00.000Z",
9  "runtime": "bun"
10}

Sanitization

Vestig automatically detects and sanitizes sensitive data to prevent accidental PII exposure in logs.

Default Sensitive Fields

These field names are automatically redacted:

password, pass, pwd
token, access_token, refresh_token
api_key, apikey, secret
authorization, bearer, auth
session_id, sessionid, cookie
credit_card, creditcard, cvv
ssn, social_security

Pattern-Based Detection

Vestig also detects patterns in values:

typescript

1log.info('User data', {
2  email: 'john@example.com',     // → jo***@example.com
3  card: '4111 1111 1111 1111',   // → ****1111
4  token: 'eyJhbGciOiJIUzI1NiI...' // → [JWT_REDACTED]
5})

Custom Sensitive Fields

Add your own sensitive field patterns:

typescript

1const logger = createLogger({
2  sanitize: true,
3  sanitizeFields: ['mySecret', 'internalKey']
4})
5 
6logger.info('Data', { mySecret: 'value' })
7// → { mySecret: '[REDACTED]' }

Context Propagation

Automatically correlate logs across your entire request lifecycle using AsyncLocalStorage.

Setting Up Context

typescript

1import { withContext, createCorrelationContext, log } from 'vestig'
2 
3// In your middleware
4app.use((req, res, next) => {
5  const ctx = createCorrelationContext()
6  // ctx = { requestId, traceId, spanId }
7 
8  withContext(ctx, () => {
9    log.info('Request started')
10    next()
11  })
12})

Accessing Context

All logs within the context automatically include correlation IDs:

json

1{
2  "level": "info",
3  "message": "Request started",
4  "context": {
5    "requestId": "550e8400-e29b-41d4-a716-446655440000",
6    "traceId": "0af7651916cd43dd8448eb211c80319c",
7    "spanId": "b7ad6b7169203331"
8  }
9}

Async Support

Context is preserved across async operations:

typescript

1withContextAsync({ requestId: 'req-123' }, async () => {
2  await db.query('SELECT ...')
3  log.info('Query completed') // Still has requestId
4})

Child Loggers

Create namespaced loggers for different parts of your application:

typescript

1const logger = createLogger({ level: 'info' })
2 
3// Create child loggers
4const dbLogger = logger.child('database')
5const apiLogger = logger.child('api')
6const authLogger = logger.child('auth')
7 
8dbLogger.info('Query executed')
9// → namespace: "database"
10 
11apiLogger.info('Request received')
12// → namespace: "api"

Chained Namespaces

Child loggers can be nested:

typescript

1const appLogger = logger.child('app')
2const userService = appLogger.child('user-service')
3 
4userService.info('User created')
5// → namespace: "app:user-service"

Overriding Config

Child loggers can override parent configuration:

typescript

1const debugLogger = logger.child('debug', { level: 'trace' })
2debugLogger.trace('Very detailed info')

Error Handling

Vestig serializes errors with full stack traces:

typescript

1try {
2  await riskyOperation()
3} catch (error) {
4  log.error('Operation failed', error)
5}

Output includes:

json

1{
2  "level": "error",
3  "message": "Operation failed",
4  "error": {
5    "name": "TypeError",
6    "message": "Cannot read property 'x' of undefined",
7    "stack": "TypeError: Cannot read property..."
8  }
9}

Runtime Detection

Vestig automatically detects the runtime environment:

typescript

1import { RUNTIME, CAPABILITIES } from 'vestig'
2 
3console.log(RUNTIME)
4// → 'node' | 'bun' | 'deno' | 'edge' | 'browser'
5 
6console.log(CAPABILITIES)
7// → { hasAsyncLocalStorage: true, hasConsole: true, ... }

Features

Deep dive into Vestig's core features.

Structured Output

Vestig outputs logs as JSON by default in production, making them easy to parse and analyze with tools like Datadog, Splunk, or CloudWatch.

typescript

1import { log } from 'vestig'
2 
3log.info('User action', { userId: '123', action: 'click' })

Output:

json

1{
2  "level": "info",
3  "message": "User action",
4  "metadata": {
5    "userId": "123",
6    "action": "click"
7  },
8  "timestamp": "2024-01-15T10:30:00.000Z",
9  "runtime": "bun"
10}

Sanitization

Vestig automatically detects and sanitizes sensitive data to prevent accidental PII exposure in logs.

Default Sensitive Fields

These field names are automatically redacted:

password, pass, pwd
token, access_token, refresh_token
api_key, apikey, secret
authorization, bearer, auth
session_id, sessionid, cookie
credit_card, creditcard, cvv
ssn, social_security

Pattern-Based Detection

Vestig also detects patterns in values:

typescript

1log.info('User data', {
2  email: 'john@example.com',     // → jo***@example.com
3  card: '4111 1111 1111 1111',   // → ****1111
4  token: 'eyJhbGciOiJIUzI1NiI...' // → [JWT_REDACTED]
5})

Custom Sensitive Fields

Add your own sensitive field patterns:

typescript

1const logger = createLogger({
2  sanitize: true,
3  sanitizeFields: ['mySecret', 'internalKey']
4})
5 
6logger.info('Data', { mySecret: 'value' })
7// → { mySecret: '[REDACTED]' }

Context Propagation

Automatically correlate logs across your entire request lifecycle using AsyncLocalStorage.

Setting Up Context

typescript

1import { withContext, createCorrelationContext, log } from 'vestig'
2 
3// In your middleware
4app.use((req, res, next) => {
5  const ctx = createCorrelationContext()
6  // ctx = { requestId, traceId, spanId }
7 
8  withContext(ctx, () => {
9    log.info('Request started')
10    next()
11  })
12})

Accessing Context

All logs within the context automatically include correlation IDs:

json

1{
2  "level": "info",
3  "message": "Request started",
4  "context": {
5    "requestId": "550e8400-e29b-41d4-a716-446655440000",
6    "traceId": "0af7651916cd43dd8448eb211c80319c",
7    "spanId": "b7ad6b7169203331"
8  }
9}

Async Support

Context is preserved across async operations:

typescript

1withContextAsync({ requestId: 'req-123' }, async () => {
2  await db.query('SELECT ...')
3  log.info('Query completed') // Still has requestId
4})

Child Loggers

Create namespaced loggers for different parts of your application:

typescript

1const logger = createLogger({ level: 'info' })
2 
3// Create child loggers
4const dbLogger = logger.child('database')
5const apiLogger = logger.child('api')
6const authLogger = logger.child('auth')
7 
8dbLogger.info('Query executed')
9// → namespace: "database"
10 
11apiLogger.info('Request received')
12// → namespace: "api"

Chained Namespaces

Child loggers can be nested:

typescript

1const appLogger = logger.child('app')
2const userService = appLogger.child('user-service')
3 
4userService.info('User created')
5// → namespace: "app:user-service"

Overriding Config

Child loggers can override parent configuration:

typescript

1const debugLogger = logger.child('debug', { level: 'trace' })
2debugLogger.trace('Very detailed info')

Error Handling

Vestig serializes errors with full stack traces:

typescript

1try {
2  await riskyOperation()
3} catch (error) {
4  log.error('Operation failed', error)
5}

Output includes:

json

1{
2  "level": "error",
3  "message": "Operation failed",
4  "error": {
5    "name": "TypeError",
6    "message": "Cannot read property 'x' of undefined",
7    "stack": "TypeError: Cannot read property..."
8  }
9}

Runtime Detection

Vestig automatically detects the runtime environment:

typescript

1import { RUNTIME, CAPABILITIES } from 'vestig'
2 
3console.log(RUNTIME)
4// → 'node' | 'bun' | 'deno' | 'edge' | 'browser'
5 
6console.log(CAPABILITIES)
7// → { hasAsyncLocalStorage: true, hasConsole: true, ... }