lite_logger 0.3.1

A fast, lightweight, and customizable logging utility for Dart & Flutter — with colored output, emoji icons, log filtering, and powerful formatting.

LiteLogger

A fast, lightweight, and customizable logging utility for Dart & Flutter — with colored output, emoji icons, log filtering, and powerful formatting.

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Features

• Log Level Filtering: Control output visibility (error, warning, success, info, step, debug)
• Colorized Output: ANSI terminal colors for instant visual clarity
• Emoji Indicators: Makes reading console logs effortless
• Lazy Message Evaluation: Prevents unnecessary computation
• Custom Formatting: Fully configurable message templates
• Callback Support: Redirect logs to file, cloud, or analytics
• Global Enable/Disable Switch

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Getting Started

final logger = LiteLogger(
    name: 'MyApp',          // Optional: identify the logger in output
    enabled: true,
    minLevel: LogLevel.debug, // show all levels
);

logger.info('Application started');
logger.step('Loading configuration...');
logger.debug(() => 'Debug timestamp: ${DateTime.now().millisecondsSinceEpoch}');
logger.success('Configuration loaded');
logger.warning('Low disk space');
logger.error('Unable to access database');

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Advanced Configuration

final logger = LiteLogger(
  name: 'MyService',        // Logger name for identification
  enabled: true,
  minLevel: LogLevel.debug,
  timestamp: (dt) => '[${dt.toIso8601String()}]',
  format: '@{color}@{timestamp} @{icon} [@{level}] @{message}',
  // output: LogOutput.auto (default) | LogOutput.print | LogOutput.developerLog
  callback: (raw, colored, level) {
    // Save logs to file or send to a remote endpoint
  },
);

<｜tool▁calls▁begin｜><｜tool▁call▁begin｜> read_file

Supported Format Tokens

Token	Description
@{color}	ANSI color escape
@{timestamp}	Formatted timestamp
@{icon}	Emoji per LogLevel
@{level}	Short log label
@{message}	Content of the log

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Log Filtering Example

const logger = LiteLogger(minLevel: LogLevel.warning);

logger.log('This is info', LogLevel.info);     // ❌ Not logged
logger.log('This is warning', LogLevel.warning); // ✅ Logged
logger.log('This is error', LogLevel.error);     // ✅ Logged

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Using Callback for Custom Output

const logger = LiteLogger(
  callback: (raw, colored, level) {
    sendToServer({'level': level.text, 'message': raw});
  },
);

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Logger Naming

Use the name parameter to identify different loggers in your application. This is especially useful when you have multiple loggers for different components.

final apiLogger = LiteLogger(name: 'API');
final dbLogger = LiteLogger(name: 'Database');
final authLogger = LiteLogger(name: 'Auth');

apiLogger.info('Fetching user data');
dbLogger.debug('Executing query...');
authLogger.warning('Token expiring soon');

Output with names:

[API] [12:34:56] 💡 [INFO] Fetching user data
[Database] [12:34:56] 🧠 [DBUG] Executing query...
[Auth] [12:34:57] ⚠️ [WARN] Token expiring soon

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Output Methods

LiteLogger supports two output methods controlled by the output parameter (LogOutput enum):

• LogOutput.auto (default): Prefers developer.log(), which keeps ANSI colors intact. print() output from a Flutter app is forwarded through logcat/syslog, which escapes the ESC byte (\x1B → ^[) and destroys colors (the flutter: ^[[36m... symptom). The single exception is release/product builds, where developer.log() output is not surfaced — there print() is used so logs remain visible.

  • NOTE: developer.log() needs a debugger/DevTools attached to be visible. For plain dart run terminals without a debugger, pass output: LogOutput.print.

• LogOutput.print: Always uses print() for maximum compatibility

  • Works reliably in packages and apps where developer.log() output may not surface
  • Produces standard console output
  • May include platform-specific prefixes (e.g., I/flutter in Flutter)
  • On Flutter mobile, ANSI colors are escaped by logcat (see above)

• LogOutput.developerLog: Always uses developer.log() from dart:developer

  • Cleaner output with less platform noise
  • Better integration with development tools
  • Supports structured logging metadata

// Auto (default): developer.log() in debug, print() in release
final logger1 = LiteLogger(name: 'App');

// Always print() — e.g. plain `dart run` terminals
final logger2 = LiteLogger(name: 'App', output: LogOutput.print);

// Always developer.log()
final logger3 = LiteLogger(name: 'App', output: LogOutput.developerLog);

The old usePrint boolean is deprecated in favor of output but still fully supported: usePrint: true behaves as output: LogOutput.print, usePrint: false as output: LogOutput.developerLog, and an explicitly passed usePrint takes precedence over output. Migration is optional — existing code keeps compiling and behaving as before.

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License

Licensed under the MIT License — free for personal and commercial use.

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Contributing

Contributions, bug reports, and ideas are always welcome!