High-performance JavaScript R-tree-based 2D spatial index
RBush is a high-performance JavaScript library for 2D spatial indexing of points and rectangles. It's based on an optimized R-tree data structure with bulk insertion support. Spatial index is a special data structure for points and rectangles that allows you to perform queries like "all items within this bounding box" very efficiently (e.g. hundreds of times faster than looping over all items). It's most commonly used in maps and data visualizations. The demos contain visualization of trees...
OCaml-Reins is a data structure library for O'Caml that includes cursor based iterators, a collection of functors to minimize client-side boilerplate, a powerful on-line benchmarking system and Quickcheck style testing infrastructure.