API Reference

Severity

enum Severity {
  Silly = 0,
  Trace = 1,
  Debug = 2,
  Info = 3,
  Warn = 4,
  Error = 5,
  Fatal = 6,
}

LogRecord

interface LogRecord {
  severity: Severity;
  severityName: string;
  timestamp: Date;
  message: string;
  meta: LogMeta;
}

Core Interfaces

type LogMeta = Record<string, unknown>;

interface Processor {
  process(log: LogRecord): LogRecord;
}

interface Transport {
  formatter?: Formatter;
  capture(log: LogRecord): void;
  flush?(): Promise<void>;
  close?(): Promise<void>;
}

interface Formatter {
  format(log: LogRecord): string;
}

flush() leaves a transport open. close() flushes pending records and releases transport resources. Both methods are optional for synchronous transports.

Logger Creation

• createLogger(options): creates a structured logger facade.
• createNamedLogger(options): creates a logger and adds a logger metadata field.
• createChildLogger(logger, meta): creates a logger with inherited metadata.
• createLoggerFacade(logger): wraps an existing logger with convenience methods.

Processors

• CompositeProcessor
• DefaultsProcessor
• RedactProcessor
• ErrorProcessor

Transports

• ConsoleTransport
• MemoryTransport
• CompositeTransport
• LineConsoleTransport
• WriterTransport

type LogWriter = (output: string, log: LogRecord) => void;

class WriterTransport implements Transport {
  constructor(formatter: Formatter, write: LogWriter);
}

CompositeTransport forwards lifecycle operations to its resolved child transports. LineConsoleTransport supports flush() and close() for its buffered writes.

Formatters

• PrettyFormatter
• JsonFormatter
• TextFormatter
• PrintfFormatter