edhedges / learngitbranching

An interactive git visualization to challenge and educate!

LearnGitBranching

LearnGitBranching is a git repository visualizer, sandbox, and series of educational tutorials and challenges. Its primary purpose is to help developers understand git through the power of visualization (something that's absent when working on the command line).

You can input a variety of commands into LearnGitBranching (LGB) -- as commands are processed, the nearby commit tree will dynamically update to reflect the effects of each command:

This visualization combined with tutorials and "levels" can help both beginners and intermediate developers polish their version control skills. A quick demo is available here: http://pcottle.github.com/learnGitBranching/?demo

Or you can launch the application normally here: http://pcottle.github.com/learnGitBranching/

Sandbox Mode

By default the application launches in "sandbox mode" with a basic repository already created. Here you can enter commands and mess around with a repository as much as you like. Keep in mind you can

• undo to undo the effects of the last command
• reset to start over from a clean slate (works in levels too)
• git clone to play with remote repositories!

Sandbox mode can be great for demonstrating something to a friend, but the real learning is with levels...

Levels

Type levels to see the available lessons / challenges (and which ones you have solved so far). Each level series aims to teach some high-level git concept, and each tab of levels separates major worlds of info (like remote repositories versus local).

For some added fun, there is a "git golf" concept where we keep track of how many commands you use to solve each level. See if you can match all of our records!

Level Builder

You can build levels with build level. The dialog will walk you through the process, and at the end you can export level to get a JSON blob. Paste that in a gist or directly into an issue and I can check it out / merge in your changes! You can also share this level directly with friends by having them run "import level" or simply specify a gist ID in the url params like so: http://pcottle.github.io/learnGitBranching/?gist_level_id=a84407351f9c9f0cb241

Reporting Bugs / Opening Issues

When reporting bugs, try running the command debug_copyTree() in your JS console when in a state just before reproducing a bug. This can avoid having to copy over all the commands you used to get into a specific state. (I can then use the importTreeNow command to get to that exact state)

How the app works / Contributing functionality

LearnGitBranching is a pretty simple application (from a technical perspective). There's no backend database or any AJAX requests -- it's a 100% clientside application written in Javascript. The production version (on github.io) literally just serves up an html page with some JS and CSS. The rest of the magic lies in the 9k+ lines of Javascript :P

Because the app contains a lot of code, I have written everything into Nodejs-style modules. The modules are packaged together with the Browserify and then sent down in a format the browser can understand.

As of December 2013, I've migrated the build process to use Grunt >0.4, since the older version was giving a lot of people build headaches. It should be fairly rock solid now!

Here is the high level process of the build:

• Code is written into the node.js modules which require other modules
• CSS is written into just one stylesheet (theres not a whole ton of styling)
• New HTML is written into a template html file (template.index.html). Only needed for new views
• The app is "built", which outputs:
  • index.html in the root directory
  • CSS and JS files in ./build directory
• If the app is being built for production, then these CSS and JS files are hashed (to bust caches) and tests are run
• That's it!

Thus, if you build the app locally, all you have to do in order to run the app is just open up index.html in the root directory of the repo. Pretty simple

Building yourself / Contributing Functionality

For contributing core functionality in the app, you'll probably want to test your changes at least once before submitting a pull request. That means you'll need the "Grunt.js" build tool to build the app:

http://gruntjs.com/getting-started

You'll also need npm to download all the dependencies of the project.

The general workflow / steps are below:

git clone <your fork of the repo>
cd learnGitBranching
npm install # to install all the node modules I depend on

git checkout -b newAwesomeFeature
vim ./src/js/git/index.js # some changes
grunt fastBuild # skips tests and linting, faster build

# after building you can open up your browser to the index.html
# file generated and see your changes

vim ./src/js/git/index.js # more changes
grunt build # runs tests and lint

git commit -am "My new sweet feature!"
git push
# go online and request a pull

Helpful Folks

A big shoutout to these brave souls for extensively testing our sandbox and finding bugs and/or inconsistencies:

• Nikita Kouevda
• Maksim Ioffe
• Dan Miller

And the following heroes for assisting in translating:

• Jake Chen
• 우리깃 ("urigit")
• "bcho"
• "scientific-coder"
• "ace-coder"
• Joël Thieffry
• Jens Bremmekamp ("nem75")
• "hilojack"
• Ming-Hsuan-Tu ("twmht")
• Mikhail Usov ("mikhailusov")
• Matias Garcia Isaia ("mgarciaisaia")
• Marc-Olivier Arsenault ("marcolivierarsenault")
• Eroany H Leader ("lhyqy5")
• Honorat ("ahonorat")

Also huge shoutout for everyone who has put up a pull request that was pulled! Check out the 30+ contributors we have in the Contributors View

And everyone who has reported an issue that was successfully closed!