Logger

A simple, cross-platform logger with support for debug, info, warning, success, error messages, and Promise loading indicators. Works in both Node.js and browser environments.

Installation

# Using npm
npm install @dolgikh-maks/logger

# Using yarn
yarn add @dolgikh-maks/logger

Philosophy of the instrument

When creating @dolgikh-maks/logger, I was guided by the principles:

• Minimalism: No configurations longer than 100 lines
• Predictability: Consistent behavior everywhere
• Performance: Zero overhead when debug is off
• Developer Experience: Easy-to-read logs = faster problem detection

Key advantages

1. Context isolation. Each module has its own scope, which eliminates confusion when components are running in parallel.
2. Visual hierarchy. Colored indicators (🔵 info, 🟢 success, 🟡 warning, 🔴 error) allow you to instantly assess the situation.
3. Flexible debugging. The setDebug() flag enables detailed logs only when needed, without cluttering production.
4. Timers out of the box. The loading() method automatically measures the execution time of asynchronous operations, which is critical for optimization.
5. Cross-platform compatibility. A unified API for browsers and Node.js. The terminal even has an animated spinner for long operations.

Usage

Importing

import createLogger from '@dolgikh-maks/logger';

const logger = createLogger({ scope: 'MyApp' });

• scope — a string to prefix all logs. Helps identify the module or feature producing the logs.

Methods

setDebug(enabled: boolean)

Enables or disables debug messages.

logger.setDebug(true);
logger.setDebug(false);

Example Output:

🔵 [MyApp]: Debug is enabled
🔵 [MyApp]: Debug is disabled

debug(message: string, ...args: any[])

Logs a debug message only if debugging is enabled.

logger.setDebug(true);
logger.debug('This is a debug message');

Example Output:

⚪ [MyApp]: This is a debug message

info(message: string, ...args: any[])

Logs an informative message.

logger.info('Application started');

Example Output:

🔵 [MyApp]: Application started

success(message: string, ...args: any[])

Logs a success message.

logger.success('Data loaded successfully');

Example Output:

🟢 [MyApp]: Data loaded successfully

warn(message: string, ...args: any[])

Logs a warning message.

logger.warn('Deprecated API usage');

Example Output:

🟡 [MyApp]: Deprecated API usage

error(message: string, ...args: any[])

Logs an error message.

logger.error('Failed to fetch data');

Example Output:

🔴 [MyApp]: Failed to fetch data

loading<T>(comment: string, promise: Promise<T>): Promise<T>

Shows a loading indicator while a Promise is pending. Automatically logs success or failure when the promise resolves or rejects. Works differently in Node.js and browser environments:

• Browser — simple console.log with timing.
• Node.js — animated spinner in terminal if TTY is available.

const fetchData = new Promise((resolve) => setTimeout(() => resolve('Done'), 1000));

logger.loading('Fetching data', fetchData).then(result => {
  console.log(`Result: ${result}`);
});

Example Output (Browser):

🟢 [MyApp]: Fetching data (1002ms)
Result: Done

Example Output (Node.js):

🔄 [MyApp]🐳
🔄 [MyApp]  🐳
🔄 [MyApp]    🐳
🔄 [MyApp]      🐳
🟢 [MyApp]: Fetching data
Result: Done

Example Combined Usage

const logger = createLogger({ scope: 'App' });

logger.setDebug(true);
logger.info('Starting application...');
logger.debug('Debugging mode is on');

const asyncTask = new Promise((resolve) => setTimeout(resolve, 2000));
await logger.loading('Performing async task', asyncTask);

logger.success('Application finished');

Output (Node.js):

🔵 [App]: Starting application...
⚪ [App]: Debugging mode is on
🔄 [App] 🐳
🔄 [App]   🐳
🟢 [App]: Performing async task
🟢 [App]: Application finished