heimdalljs-logger

What is heimdalljs-logger?

heimdalljs-logger is a logging utility designed to work with the heimdalljs performance monitoring library. It provides a simple and efficient way to log messages with different levels of severity, making it easier to track and debug performance issues in your application.

What are heimdalljs-logger's main functionalities?

Basic Logging

Allows you to log messages with different levels of severity (info, warn, error).

const logger = require('heimdalljs-logger')('my-app');
logger.info('This is an info message');
logger.warn('This is a warning message');
logger.error('This is an error message');

Custom Log Levels

Enables you to define custom log levels for more granular control over logging.

const logger = require('heimdalljs-logger')('my-app');
logger.addLevel('debug', 1000);
logger.debug('This is a debug message');

Contextual Logging

Allows you to add contextual information to your log messages, making it easier to understand the context in which a log message was generated.

const logger = require('heimdalljs-logger')('my-app');
logger.info('Starting process', { processId: 12345 });

Other packages similar to heimdalljs-logger

winston

Winston is a versatile logging library with support for multiple transports (e.g., console, file, HTTP). It offers more advanced features like log formatting, log levels, and custom transports, making it a more comprehensive solution compared to heimdalljs-logger.

bunyan

Bunyan is a simple and fast JSON logging library. It provides a straightforward API for logging and includes features like log levels, serializers, and log rotation. Bunyan's focus on JSON logging makes it a good choice for structured logging, which is not a primary focus of heimdalljs-logger.

pino

Pino is a low-overhead logging library designed for high-performance applications. It offers features like log levels, serializers, and log redirection. Pino's emphasis on performance and low overhead makes it a suitable alternative to heimdalljs-logger for applications where logging performance is critical.

README

Usage

With no Heimdall Tree

var logger = require('heimdalljs-logger')('foo');

logger.trace('trace message');
logger.debug('debug message');
logger.info('info message');
logger.warn('warn message');
logger.error('error message');

console.log('app message');

DEBUG=foo DEBUG_LEVEL=trace foo
# =>  trace message
# ... debug message
# ... info message
# ... warn message
# ... error message
# ... app message

foo
# =>  app message

DEBUG=foo DEBUG_LEVEL=warn foo
# =>  warn message
# ... error message
# ... app message

With a Heimdall Tree

var heimdall = require('heimdalljs');
var config  = require('heimdalljs').configFor('logging');

config.matcher = (id) => /hai/.test(id.name);
config.depth = 2;

var logger = require('heimdalljs-logger')('foo');

heimdall.start('a');
heimdall.start('bhai');
heimdall.start('c');
heimdall.start('dhai');

logger.warn('warn message');
// => foo [bhai -> dhai] warn message