Turf.js is an open source JavaScript library for advanced geospatial analysis that allows for spatial operations to be preformed in the browser. The full build of Turf is around 500kb which is a fair bit of javascript to load. You can use https://turfjs-builder.herokuapp.com/ to create a custom build of the library containing only the modules you need instead of using the content delivery network (CDN) of the library. This task sheet with get you started with using different Turf.js functions such as creating points, polygons, and calculating distance and area.