Contributing

Development Workflow

Fork the repo and clone to your local machine. Run npm install to install all required dependencies.
You can then run several commands:

npm run start launches webpack-dev-server for the UI component only at http://localhost:8080/panel.html. Any changes made to files will be watched - refresh the page to see changes.
npm run dev bundles and copies files to /dist. You can load this folder as an unpacked extension into Chrome. If you make any changes to the source code, press Ctrl+R on the chrome://extensions page to reload the extension. You can also load it as a temporary add-on into Firefox. The extension can be reloaded from about:debugging.
npm run prod bundles a production build into /dist. It strips all console.* statements and minifies output files.

When you're ready to submit your changes, make a pull request to the master branch.

Where to contribute

Performance

Reducing bundle size by importing Blueprint components individually
Reducing lag between button click and popup showing
Reducing lag between page content load and overlay appearing. Consider splitting common dependencies of fb.js and tw.js into a file loaded in the background

Testing

Creating a test suite

Refactoring

Refactoring components to manage local state with MobX instead of React.setState
Refactoring Toast component to follow React idioms

Miscellaneous

Implementing TODOs marked in codebase
Fixing code style violations

Coding conventions

ES2015 where possible
Use presentational and container components
Postfix arrays with Arr (eg. stringArr = ["Targaryen", "GoT"])
Use semicolons ;
Tabs for indentation
" over '
jsonObject[property] over jsonObject.property

.eslintrc.json helps lint this coding style.