What is "flapjax"

Flapjax is a programming language built atop JavaScript. It provides a spreadsheet-like dataflow computation style ( functional reactive programming), making it easy to create reactive Web pages without the burden of callbacks and potentially inconsistent mutation. Flapjax can be thought of in two ways: either as a library, for use in regular JavaScript programs, or as a new language that the compiler converts into generic JavaScript. In either case, the resulting programs can be run in a regular Web browser. In addition, Flapjax comes with persistent storage and a simple API that masks the complexity of using AJAX, along with sharing and access-control for server data.

The Flapjax compiler is written in Haskell.