node-json-logger

Simply, output logs to STDOUT in JSON

Install

npm i node-json-logger

Usage

const Logger = require('node-json-logger');
const logger = new Logger();

logger.info();
logger.info('message');
logger.info('message','message','message');
logger.info({ data: 'data' });
logger.info({ data1: 'data' }, { data2: 'data' });
logger.info('message', { data1: 'data' }, 'message', { data2: 'data' }, 'message');

Outputs:

{"timestamp":"2001-03-14T01:00:00.000Z","level":"info"}
{"timestamp":"2001-03-14T01:00:00.000Z","level":"info","message":"message"}
{"timestamp":"2001-03-14T01:00:00.000Z","level":"info","message":"message","message1":"message","message2":"message"}
{"timestamp":"2001-03-14T01:00:00.000Z","level":"info","data":"data"}
{"timestamp":"2001-03-14T01:00:00.000Z","level":"info","data1":"data","data2":"data"}
{"timestamp":"2001-03-14T01:00:00.000Z","level":"info","message":"message","data1":"data","message1":"message","data2":"data","message2":"message"}

API

logger.xxx(message?, ...)

Note:

• xxx is one of the Levels

Arguments:

• message: Specify a message as string or object.

Levels

• trace
• debug
• info
• warn
• error
• fatal

Configuration

level

Specify output level. (optional, default is debug)

const Logger = require('node-json-logger');
const logger = new Logger({ level: 'error'});

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

Output:

{"timestamp":"2001-03-14T01:00:00.000Z","level":"error","message":"message"}
{"timestamp":"2001-03-14T01:00:00.000Z","level":"fatal","message":"message"}

Level and output:

| | trace | debug | info | warn | error | fatal | |:---------------------|:------|:------|:-----|:-----|:------|:------| | { level: 'trace' } | O | O | O | O | O | O | | { level: 'debug' } | - | O | O | O | O | O | | { level: 'info' } | - | - | O | O | O | O | | { level: 'warn' } | - | - | - | O | O | O | | { level: 'error' } | - | - | - | - | O | O | | { level: 'fatal' } | - | - | - | - | - | O | | { level: 'none' } | - | - | - | - | - | - |

loggerName

Specify the name of the logger. Useful when logging from different files.

const Logger = require('node-json-logger');
const logger = new Logger({ loggerName: 'server/index.js' });

logger.info('message');

Output:

{"timestamp":"2001-03-14T01:00:00.000Z","level":"info","loggerName":"server/index.js","message":"message"}

timestamp

Specify enable or disable timestamp. (optional, default is true)

const Logger = require('node-json-logger');
const logger = new Logger({ timestamp: false });

logger.info('message');

Output with disabled timestamp:

{"level":"info","message":"message"}

timezone

Specify locale timezone. (optional, default is UTC)

const Logger = require('node-json-logger');
const logger = new Logger({timezone: 'America/Sao_Paulo'});

logger.info('message');

Output with specific timezone:

{"timestamp":"2018-10-25T15:32:43.318Z","level":"info","message":"message"}

Same output with default timezone (UTC):

{"timestamp":"2018-10-25T18:32:43.318Z","level":"info","message":"message"}

Click here to see the list with all available timezones.

License

MIT

Copyright ©2018 Hiroaki SHIBUKI a.k.a. hidori