debug 2.1.3

small debugging utility

Homepage: https://github.com/visionmedia/debug

Platform: npm

Language: JavaScript

License: MIT

View on registry: https://www.npmjs.com/package/debug/

Install: npm install debug


debug

tiny node.js debugging utility modelled after node core's debugging technique.

Installation

$ npm install debug

Usage

With debug you simply invoke the exported function to generate your debug function, passing it a name which will determine if a noop function is returned, or a decorated console.error, so all of the console format string goodies you're used to work fine. A unique color is selected per-function for visibility.

Example app.js:

var debug = require('debug')('http')
 , http = require('http')
 , name = 'My App';
// fake app
debug('booting %s', name);
http.createServer(function(req, res){
 debug(req.method + ' ' + req.url);
 res.end('hello\n');
}).listen(3000, function(){
 debug('listening');
});
// fake worker of some kind
require('./worker');

Example worker.js:

var debug = require('debug')('worker');
setInterval(function(){
 debug('doing some work');
}, 1000);

The DEBUG environment variable is then used to enable these based on space or comma-delimited names. Here are some examples:

debug http and worker

debug worker

Windows note

On Windows the environment variable is set using the set command.

 set DEBUG=*,-not_this

Then, run the program to be debugged as usual.

Millisecond diff

When actively developing an application it can be useful to see when the time spent between one debug() call and the next. Suppose for example you invoke debug() before requesting a resource, and after as well, the "+NNNms" will show you how much time was spent between calls.

When stdout is not a TTY, Date#toUTCString() is used, making it more useful for logging the debug information as shown below:

Conventions

If you're using this in one or more of your libraries, you should use the name of your library so that developers may toggle debugging as desired without guessing names. If you have more than one debuggers you should prefix them with your library name and use ":" to separate features. For example "bodyParser" from Connect would then be "connect:bodyParser".

Wildcards

The * character may be used as a wildcard. Suppose for example your library has debuggers named "connect:bodyParser", "connect:compress", "connect:session", instead of listing all three with DEBUG=connect:bodyParser,connect:compress,connect:session, you may simply do DEBUG=connect:*, or to run everything using this module simply use DEBUG=*.

You can also exclude specific debuggers by prefixing them with a "-" character. For example, DEBUG=*,-connect:* would include all debuggers except those starting with "connect:".

Browser support

Debug works in the browser as well, currently persisted by localStorage. Consider the situation shown below where you have worker:a and worker:b, and wish to debug both. Somewhere in the code on your page, include:

window.myDebug = require("debug");

("debug" is a global object in the browser so we give this object a different name.) When your page is open in the browser, type the following in the console:

myDebug.enable("worker:*")

Refresh the page. Debug output will continue to be sent to the console until it is disabled by typing myDebug.disable() in the console.

a = debug('worker:a');
b = debug('worker:b');
setInterval(function(){
 a('doing some work');
}, 1000);
setInterval(function(){
 b('doing some work');
}, 1200);

Web Inspector Colors

Colors are also enabled on "Web Inspectors" that understand the %c formatting option. These are WebKit web inspectors, Firefox (since version 31) and the Firebug plugin for Firefox (any version).

Colored output looks something like:

stderr vs stdout

You can set an alternative logging method per-namespace by overriding the log method on a per-namespace or globally:

Example stdout.js:

var debug = require('debug');
var error = debug('app:error');
// by default stderr is used
error('goes to stderr!');
var log = debug('app:log');
// set this namespace to log via console.log
log.log = console.log.bind(console); // don't forget to bind to console!
log('goes to stdout');
error('still goes to stderr!');
// set all output to go via console.info
// overrides all per-namespace log settings
debug.log = console.info.bind(console);
error('now goes to stdout via console.info');
log('still goes to stdout, but via console.info now');

Authors

  • TJ Holowaychuk
  • Nathan Rajlich

License

(The MIT License)

Copyright (c) 2014 TJ Holowaychuk <tj@vision-media.ca>

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

веселые картинки развлекательные гифки интресные факты смешные видео смешные истории из соцсетей

Development Dependencies

Dependencies

  • ms 0.7.0

GitHub Repository

visionmedia/debug visionmedia/debug

tiny node.js & browser debugging utility for your libraries and applications

Language: JavaScript

Created: November 29, 2011 02:23

Last updated: March 28, 2015 02:14

Last pushed: March 27, 2015 00:18

Size: 1.14 MB

Stars: 1,696

Forks: 166

Watchers: 47

Open issues: 20

Top Contributors

Nathan Rajlich TJ Holowaychuk Robert Sköld Dário Stephen Mathieson Zeus Gómez Marmolejo Tim Oxley Jean Ponchon Moo Yeol, Lee (Prescott) G. Scott Olson Amir Abu Shareb Jared Forsyth Hayko Koryun Elan Shanker David M. Lee Daniel Vicory Amir Saboury mykwillis Ben Noordhuis Anton Wilhelm

Releases

  • 2.1.3 - March 13, 2015 18:50
  • 2.1.2 - March 02, 2015 01:39
  • 2.1.1 - December 29, 2014 21:51
  • 2.1.0 - October 15, 2014 21:58
  • 2.0.0 - September 01, 2014 07:21
  • 1.0.4 - July 15, 2014 23:16
  • 1.0.3 - July 09, 2014 16:16
  • 1.0.2 - June 11, 2014 00:50
  • 1.0.1 - June 06, 2014 20:23
  • 1.0.0 - June 05, 2014 03:55
See all 25 releases

Related Projects

visionmedia/debug
tiny node.js & browser debugging utility for your libraries and applications
Bower - JavaScript - Published 19 days ago - 1,696 stars
debug-list 1.0.2
Small utility for managing multiple visionmedia/debug
npm - JavaScript - MIT - Updated 3 months ago
depugger 1.0.0
small debugging utility
npm - JavaScript - MIT - Updated 7 months ago
neo-debug 0.0.2
A more configurable debug utility module.
npm - JavaScript - MIT - Updated 10 months ago
adamvr-debug 0.7.2
small debugging utility
npm - JavaScript - Published over 1 year ago - 1,696 stars
веселые картинки развлекательные гифки интресные факты смешные видео смешные истории из соцсетей