This is flann.js, a port of C++ FLANN library to JavaScript.
Fast Library for Approximate Nearest Neighbors FLANN is a C++ library written by Marius Muja and David G. Lowe.
One can use JavaScript version to do in-browser image processing, or pattern recognition.
Ported by Anton Grbin using emscripten.
In examples/shell-examples/ one can find few examples of usage in Node.
examples/web-examples/ shows how this library can be used on web.
Plane example generates 100 random pivot points in plane and assigns random color to each of them.
Autotuned index is built based on those pivot points.
Afterwards, new random points are generated and they are colored with color of nearest pivot point as returned by Flann index.
This example is visible on gh-pages.