Hiplog NPM | npm.io

Fancy lightweight logging utility for Node.js

Installation

Prerequisites: Node.js 6+, npm 3+.

npm install --save hiplog

Usage

const { Log } = require('hiplog');
const log = new Log({ level: 'debug' });

log.debug('messages to debug an application');
log.info('a purely informational message');
log.notice('a normal but significant condition');
log.warning('warning condition');
log.error('error condition');
log.critical('the system is in critical condition');
log.alert('action must be taken immediately');
log.emergency('system is unusable');

Hiplog levels output

Objects

Objects are automatically stringified using Purdy. Small objects (< 200 characters) are inlined.

log.info('a small object:', { int: 123, bool: true, str: 'Hello' });

Hiplog small objects output

const circular = {};
circular.inner = circular;

log.info('a bigger object', {
  null: null,
  undefined,
  integer: 123,
  boolean: true,
  string: 'Hello',
  funtion: function myFunction() {},
  circular,
  array: ['one', 'two', 'three', 'four'],
});

Hiplog big objects output

Errors

Errors are displayed using jest-message-util (powered by :sparkles: babel-code-frame :sparkles:):

try {
  throw new Error('Error example');
} catch (e) {
  log.error(e);
}

Hiplog errors output

Options

`level`

type: string
default value: 'info'

Minimum level to display. All messages below this level will be ignored.

`stream`

type: Steam | function: integer -> Stream

default value:

level => (level <= 4 ? process.stderr : process.stdout)

Stream to write to.

`displayTime`

type: boolean
default value: false

Whether to display time information or not. Example:

Hiplog time output

`displayTimeFormat`

type: string
default value: 'yyyy-mm-dd HH:MM:ss.l'

Date format to display time in, when displayTime is set to true. See dateformat for possible values.

`separator`

type: string
default value: ' • '

Separator between message header and body, and also between time and and label, when displayTime is set to true;

`format`

type: function: string -> string
default value: hiplog.format

Message formatter function.

`fromEnv`

const hiplog = require('hiplog');
const log = hiplog.fromEnv();

fromEnv is a utility function that will create a new instance of Log with options taken from environment variables:

NODE_ENV:
- 'development' (default): displayTime is disabled,
- 'test': displayTime is disabled, 'level' is set to 'critical',
- 'production': use default values for each option.
LOG: sets level value.
LOG_LEVEL: alias for LOG.
LOG_TIME: when set to true or 1, enables displayTime.
LOG_TIME_FORMAT: sets displayTimeFormat value.

Note: fromEnv accepts an options parameter that allow overriding these defaults. Example:

const hiplog = require('hiplog');
const log = hiplog.fromEnv({ displayTime: false });
// displayTime will be always `false`, disregarding the value of `LOG_TIME`.