@karmaniverous/edge-logger

edge-logger

The Next.js Edge Runtime is extremely limited as to the packages it can load.

This can pose a challenge for common logging and utility packages like winston and lodash, which will fail when loaded into an edge resource.

Logging is a cross-cutting concern, and shouldn't have to care where it is executed. So this package is a simple, flexible logging utility that...

• formats logs attractively, whether output to the console or cloud services like AWS CloudWatch.
• features configurable logging levels (defaults to SysLog).
• can handle virtually any input, including circular object references.
• can truncate long strings for readability.

Installation

npm install @karmaniverous/edge-logger

Usage

import Logger from `@karmaniverous/edge-logger`;
const logger = new Logger();

logger.emerg('emergency message', { foo: 'bar' }); // rendered with console.error()
logger.alert('alert message');                     // rendered with console.error()
logger.crit('critical message');                   // rendered with console.error()
logger.error('error message');                     // rendered with console.error()
logger.warning('warning message');                 // rendered with console.warn()
logger.notice('notice message');                   // rendered with console.info()
logger.info('info message');                       // rendered with console.info()
logger.debug('debug message');                     // rendered with console.debug()
logger.log('log message');                     // rendered with console.info()

// emerg:   emergency message
// emerg:   {
// emerg:     "foo": "bar"
// emerg:   }
// alert:   alert message
// crit:    critical message
// error:   error message
// warning: warning message
// notice:  notice message
// info:    info message
// info:    log message

// debug level not rendered by default.
// Set LOG_LEVEL to 'debug' to see these.

Configuration

Set your minimum logging level with environment variable LOG_LEVEL (by default it is info).

The optional constructor config argument has the following keys:

Key	Description
defaultLevel	Default logging level (invoked by the log method). Default value set in levels object (info for default levels).
maxLevel	Maximum logging level. Default value set in levels object (info for default levels).
levels	An alternate levels definition. See below for details.

Levels Config

Here is the default levels object:

{
  emerg: { value: 0, console: 'error' },
  alert: { value: 1, console: 'error' },
  crit: { value: 2, console: 'error' },
  error: { value: 3, console: 'error' },
  warning: { value: 4, console: 'warn' },
  notice: { value: 5, console: 'info' },
  info: { value: 6, console: 'info', default: true, defaultMax: true },
  debug: { value: 7, console: 'debug' },
}

Each key will be rendered as a function on the Logger instance that takes a list of items, just like console.log().

The keys on each log level:

Key	Description
value	Supports setting the logging threshold.
console	The console function invoked by the log level.
default	true if the log method should trigger this level.
defaultMax	true if default max level.

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