JSTS
This is a fork of https://github.com/bjornharrtell/jsts with added transpilation step to support IE11.
JSTS is an ECMAScript library of spatial predicates and functions for processing geometry conforming to the Simple Features Specification for SQL published by the Open Geospatial Consortium. JSTS is also a port of the well established Java library JTS.
The primary goal of the project is to provide web mapping applications with a complete library for processing and analyzing simple geometries but JSTS can also be used as a free standing geometry library.
JSTS was made using automatic translation of the original JTS Java source via AST to AST transformation preserving the JTS API, except for the I/O related classes which has been selectively and manually ported with support for WKT, GeoJSON and OpenLayers 3+.