Core Logging

/**
 * Creates or retrieves a logger instance for a specified component name
 * @param name - The name/identifier for the logger (e.g., 'myPackage', 'webdriver:chrome')
 * @returns Logger instance with all standard and custom logging methods
 */
function getLogger(name: string): Logger;

import logger from '@wdio/logger';

// Create loggers for different components
const mainLog = logger('myApp');
const dbLog = logger('database');
const apiLog = logger('api');

// Each logger can have different settings
logger.setLevel('database', 'debug');
logger.setLevel('api', 'warn');

interface Logger {
  /**
   * Log trace-level messages (level 0)
   * @param args - Messages and objects to log
   */
  trace(...args: any[]): void;

  /**
   * Log debug-level messages (level 1)
   * @param args - Messages and objects to log
   */
  debug(...args: any[]): void;

  /**
   * Log info-level messages (level 2)
   * @param args - Messages and objects to log
   */
  info(...args: any[]): void;

  /**
   * Log warning messages (level 3)
   * @param args - Messages and objects to log
   */
  warn(...args: any[]): void;

  /**
   * Log error messages (level 4)
   * @param args - Messages and objects to log
   */
  error(...args: any[]): void;

  /**
   * Custom progress logging for dynamic terminal updates
   * Writes directly to process.stdout with cursor manipulation
   * @param msg - Progress message strings
   */
  progress(...msg: string[]): void;

  /**
   * Set the minimum log level for this logger instance
   * @param level - Log level descriptor
   */
  setLevel(level: LogLevelDesc): void;

  /**
   * Get the current log level number for this logger
   * @returns Current log level as number (0-5)
   */
  getLevel(): LogLevelNumbers;

  /** Array of regex patterns for masking sensitive data in this logger's output */
  maskingPatterns: RegExp[] | undefined;
}

import logger from '@wdio/logger';

const log = logger('myService');

// Standard logging
log.trace('Detailed execution trace');
log.debug('Debug information');
log.info('General information');
log.warn('Warning message');
log.error('Error occurred', { errorCode: 500 });

// Progress logging for dynamic updates
const total = 100;
for (let i = 0; i <= total; i += 10) {
  log.progress(`Downloading... ${i}%`);
  await new Promise(resolve => setTimeout(resolve, 100));
}
log.progress(''); // Clear progress line

// Error object logging (automatically displays stack trace)
try {
  throw new Error('Something went wrong');
} catch (error) {
  log.error('Operation failed:', error);
}

/**
 * Special logging method for dynamic terminal updates
 * Equivalent to info level but writes directly to stdout with cursor manipulation
 * Only displays in TTY environments and when log level <= info
 * @param data - Progress message strings
 */
progress(...data: string[]): void;

import logger from '@wdio/logger';

const log = logger('downloader');

// Show download progress
let downloaded = 0;
const total = 1000;

const interval = setInterval(() => {
  downloaded += 100;
  const percent = Math.round((downloaded / total) * 100);
  log.progress(`Downloading driver... ${percent}%`);
  
  if (downloaded >= total) {
    clearInterval(interval);
    log.progress(''); // Clear the progress line
    log.info('Download complete!');
  }
}, 200);

// Processing with dynamic updates
const items = ['file1.txt', 'file2.txt', 'file3.txt'];
for (let i = 0; i < items.length; i++) {
  log.progress(`Processing ${items[i]} (${i + 1}/${items.length})`);
  await processFile(items[i]);
}
log.progress(''); // Clear when done
log.info('All files processed');

/**
 * Set log level for a specific logger instance
 * @param name - Logger name/identifier
 * @param level - Log level descriptor
 */
logger.setLevel(name: string, level: LogLevelDesc): void;

import logger from '@wdio/logger';

// Set different levels for different components
logger.setLevel('database', 'debug');    // Show all database logs
logger.setLevel('api', 'warn');          // Only show API warnings and errors
logger.setLevel('verbose-module', 'silent'); // Suppress all logs

const dbLog = logger('database');
const apiLog = logger('api');

dbLog.debug('Database query executed'); // Will show (level is debug)
apiLog.debug('API request details');    // Won't show (level is warn)
apiLog.warn('API rate limit warning');  // Will show

type LogLevelDesc = 'trace' | 'debug' | 'info' | 'warn' | 'error' | 'silent';
type LogLevelNumbers = 0 | 1 | 2 | 3 | 4 | 5;