Asynchronous Logging

Winston supports asynchronous logging by using promises or callbacks in custom transports. Here’s an example using promises:

const { TransportStreamOptions } = require('winston-transport');

class AsyncTransport extends TransportStreamOptions {
  constructor(options) {
    super(options);
  }

  async log(info) {
    return new Promise((resolve, reject) => {
      setImmediate(() => this.emit('logged', info));
      // Simulate async operation
      setTimeout(() => {
        console.log(`Async log: ${info.level}: ${info.message}`);
        resolve();
      }, 1000);
    });
  }
}

const logger = winston.createLogger({
  level: 'info',
  transports: [
    new AsyncTransport()
  ]
});

logger.info('This is an async log message');