Beta Readonly scopeThe scope/category for this logger instance
Logs a debug message
Use for detailed diagnostic information useful during development and troubleshooting. Debug logs are typically disabled in production and should include technical details like internal state, intermediate values, or execution flow.
logger.debug('Cache miss, fetching from API', { key: 'user:123' });
logger.debug('Rendering component', { props: componentProps });
The log message
Optional data: LogDataOptional additional data to include with the log entry
Logs an error message
Use for failures and exceptions that prevent normal operation or indicate something has gone wrong. Error logs should always describe what failed and include relevant context to aid in diagnosis.
logger.error('Failed to fetch user data', error, { userId: 123 });
logger.error('Invalid configuration detected', undefined, { config: invalidConfig });
The log message
Optional error: ErrorOptional error object
Optional data: LogDataOptional additional data to include with the log entry
Logs an informational message
Use for significant application events that represent normal behavior. Info logs should capture key milestones, successful operations, or state transitions that are useful for understanding application flow in production.
logger.info('User authenticated', { userId: user.id });
logger.info('File uploaded successfully', { filename: 'report.pdf', size: 2048 });
The log message
Optional data: LogDataOptional additional data to include with the log entry
Logs a warning message
Use for unexpected situations that don't prevent the application from functioning but may indicate potential issues, deprecated usage, or suboptimal conditions. Warnings should be actionable and suggest something that may need attention.
logger.warn('API response time exceeded threshold', { duration: 3500, threshold: 3000 });
logger.warn('Using deprecated configuration option', { option: 'legacy_mode' });
The log message
Optional data: LogDataOptional additional data to include with the log entry
Logger service for writing log messages to configured handlers
Loggers are created from a LoggerFactory with a specific scope/category. All log messages written to a logger will be sent to all handlers configured in the factory.
Example