LogLayer

Child Loggers ​

Child loggers allow you to create new logger instances that inherit configuration, context, and plugins from their parent logger. This is particularly useful for creating loggers with additional context for specific components or modules while maintaining the base configuration.

Creating Child Loggers ​

Use the child() method to create a child logger:

typescript
const parentLog = new LogLayer({
  transport: new ConsoleTransport({
    logger: console
  })
})

const childLog = parentLog.child()

Inheritance Behavior ​

Child loggers inherit:

  1. Configuration from the parent
  2. Context data (as a shallow copy)
  3. Plugins

Configuration Inheritance ​

All configuration options are inherited from the parent:

typescript
const parentLog = new LogLayer({
  transport: new ConsoleTransport({
    logger: console
  }),
  contextFieldName: 'context',
  metadataFieldName: 'metadata',
  errorFieldName: 'error'
})

// Child inherits all configuration
const childLog = parentLog.child()

Context Inheritance ​

Context data is shallow copied from the parent:

typescript
const parentLog = new LogLayer({}).withContext({
  app: 'myapp',
  version: '1.0.0'
})

// Child inherits parent's context
const childLog = parentLog.child()
childLog.info('Hello')
// Output includes: { app: 'myapp', version: '1.0.0' }

// Add additional context to child
childLog.withContext({
  module: 'users'
})
childLog.info('User created')
// Output includes: { app: 'myapp', version: '1.0.0', module: 'users' }

// Parent's context remains unchanged
parentLog.info('Parent log')
// Output includes: { app: 'myapp', version: '1.0.0' }