@yucom/log v0.1.3

Yucom Log

Preconfigured simple logger

Install

npm install @yucom/log

Use

const log = require('@yucom/log');

// log is a root logger
log.debug('Hello world!'); // 2019-04-11T18:42:50.636-03:00 [][] DEBUG: Hello world!
log.info('Max height:', 5 * 4, 'mm') // ... INFO: Max height 20 mm
log.warning('Received', { status: 404 }) // ... WARNING: Received { "status": 404 }
log.error(new TypeError('WTF!')) // ... ERROR: TypeError: WTF! at ...(full stack trace)...

Tagged logger

This is the recommended way to use a logger. Instead of using the main log instance, create a tagged instance to better identify the source module.

//tagged logger:
let mylog = log.create('my-module')

mylog.info('Hello') // 2019-04-11T18:42:50.636-03:00 [my-module][] INFO: Hello

Log levels

The root level log reads the environment variable LOG_LEVEL. If it's not defined, all (all messages) is used. Valid level values are: all, debug, info, warning, error, none

all and debug are equivalent.

Log level can be changed in runtime:

log.setLevel('warning');

This will affect all tagged loggers also, unless they're level had been explicitly specified.

// Creates a logger with its own level
let mylog = log.create('my-module', 'error')
// You can also set its level later
mylog.setLevel('warning');

Context

If the property txid is present in context, it will be included in output.