loglevel-prefix
Minimal lightweight (0.9KB minified and gzipped) plugin for loglevel message prefixing
Installation
npm install loglevel-prefix --save
API
;
log - root logger, imported from loglevel package
options - configuration object
default_options = template: '[%t] %l:' date level name || 'root'
Plugin formats the prefix using template option as a printf-like format.
The template is a string containing zero or more placeholder tokens. Each placeholder token is replaced with the value from loglevel messages parameters. Supported placeholders are:
%t - Timestamp of message.
%l - Level of message.
%n - Name of logger.
The timestampFormatter, levelFormatter and nameFormatter is a functions for formatting corresponding values
Base usage
Browser directly
Download production version and copy to your project folder
Output
[12:53:46] WARN: prefixed message
ES6
;; ;log;
CommonJS
var log = ;var prefix = ;; // or// var log = require('loglevel-prefix')(require('loglevel')); log;
AMD
;
Custom options
;; ; log;
Output
[2017-05-29T16:53:46.000Z] Warn (global) static text: prefixed message
Example
// moduleA.js; { log;}
// moduleB.js; const logger = log; { logger;}
// moduleC.js; { const logger = log; logger;}
// main.js;; ;;; log; ; log; ;;;
Output
message from root before prefixing
[16:53:46] WARN (root): message from root after prefixing
[16:53:46] WARN (root): message from moduleA
message from moduleB
[16:53:46] WARN (moduleC): message from moduleC
Errors
// main.js;; log;; log; try ; catche log;; log; const logger = log; try ; catche logger;; logger;
Output
[16:53:46] INFO: message from root after prefixing
[16:53:46] ERROR: TypeError: You can assign a prefix only one time
[16:53:46] INFO: message from root after pre-prefixing
[16:53:46] ERROR: TypeError: Argument is not a root loglevel object
[16:53:46] INFO: message from child logger