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Lumberjack is a JavaScript utility that hijacks the browser console, makes it more beautiful and enhances it so logs can be split into more manageable chunks.

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Lumberjack is a JavaScript utility that hijacks the browser console, makes it more beautiful and enhances it so logs can be split into more manageable chunks. Lumberjack also saves everything that is logged (so you can review later) and colorizes your logs (where supported) to increase legibility.


Getting Started

  1. Copy lumberjack.js into your project.
  2. That's it!

What is Lumberjack?

Browser based applications with lots of JavaScript often result in lots of logging. Unfortunately, the single stream logging built into modern web browsers (through console.log) gets noisy as more and more messages are logged. In can become difficult to even follow the logs. Lumberjack aims to fix that.


Instead of logging everything with console.log, Lumberjack encourages you to split your logs into bite-sized chunks that map to your application's functionality. In Lumberjack, these are called streams. Streams organize your logging by name. For example:'cat').info('I do not like you.');'cat').warn('Hiss!');'dog').info('The feeling is mutual.');'dog').warn('Woof!');

Calling the "stream" method actually creates a brand new console object that you can use. This enables you to do shorthand like this:

var cat ='cat');'Here are some foods I like:'); cat.log('Rabbit'); cat.log('Chicken');

You can also create sub-streams off a stream.

var cat ='cat');
var boobie ='boobie');
var karl ='karl');

boobie.warn('Hiss!'); karl.log('Meow');'karl').log('Zzzzzzzz...');'boobie').log('I am sleepy, too');

With Lumberjack you can turn on or off logging globally or for specific sections of your code. If you don't want to hear the dog bark anymore, you can do this:'dog').off();
//or'dog');'dog').log('Bark! Bark! Bark!'); //this message isn't going to appear in the console

Even if you turn off a stream, all statements logged to it are still being recorded behind the scenes by Lumberjack. At any point while your application is running you can audit all the log statements like so:'dog').logs(); //returns an Array of every message logged to the 'dog' stream

Conversely, if you want to turn a stream on, it's just as easy:'rooster').log('qui-qui-ri-qui!'); //this message isn't going to appear in the console'rooster').on(); //or console.on('rooster');'rooster').log('COCKADOODLEDOO!'); //this message will appear in the console

Lumberjack supports all the semantic console logging functions: console.log,, console.dir, console.warn and console.error.

Color in Your Console

If your browser supports color in the console (at the moment this is Chrome and Firefox), then the stream names will appear and be colorized. This offers a little more visual distinction which can make your console easier to read. You can override the default colors when you create the stream, or at any time.

var cesar ='cesar', {color: '#999', background: '#000'});
var mickey ='mickey', {color: 'orange', background: 'beige'});

cesar.log('Hi, my name is Cesar.'); mickey.log('Hi, my name is Mickey.');

cesar.color('white'); cesar.background('red'); cesar.log('Whoa. I used to be black, but now I am red.');

mickey.color('lightblue'); mickey.background('purple'); mickey.log('Hey look at me!');


Jeff Bail


Lumberjack is licensed under the MIT Open Source license.

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