Metadata
Every log message could contain some additional context for future working with.
With pretty format (in development) metadata will be shown as a serialized object at the end of the log with it.
With JSON logs format metadata fields will be added to the displaying JSON object.
typescript
import { createLogger } from '@neodx/log';
const log = createLogger();
// message argument { foo: 'bar' }
log.info({ foo: 'bar' }, 'message %s', 'argument');If you want to log error with additional metadata, you should pass error in { err: ... } field, all other fields will be metadata:
typescript
// before
log.error(myError);
// after
log.error({ err: myError, foo: 'bar' });Also, you can provide default metatada:
typescript
import { createLogger } from '@neodx/log';
const log = createLogger({
meta: {
shared: 10
}
});
// message { shared: 10 }
log.info('message');
// message { shared: 10, foo: 'bar' }
log.info({ foo: 'bar' }, 'message');
// message { shared: 20, foo: 'bar' }
log.info({ shared: 20, foo: 'bar' }, 'message');