That is not tied to a proprietary platform
Why? Most of them (or all, no links, and I can’t bother to google them all) are ESRIs own libraries, and although OpenSource they are tied to the ESRI platform. In fact, from what I understand, 4 or 5 of them are directly tied to ArcGIS Online.
This made me feel a bit tricked. Not that there are anything wrong with ESRI releasing OpenSource code, but where there is an implicit requirement that you use their paid services, what is the use for others?
We all know OpenLayers 2 (don’t we?) and most of you probably know that the brand new OpenLayers 3 is in the making (beta 4 now!). Lots of features, a complete rewrite and heavy use of the Closure compiler.
The web-friendly, lightweight, hipster no-frills mapping library that excels in beeing un-bloated and easy to use. Just try it, seriously!
Njord.js is a vanilla JS, client side lib for lightweight geoprocessing, envisioned to compete with jsts and heavily inspired by Shapely. It’s written by yours truly and is under development.
KuGIS is a browser-driven GIS-application with support for a lot of spatial analysis. Driven by Leaflet and JSTS. Really shows what you can do in the browser these days.
Although I haven’t used it myself I’ve heard some good things about this lib, actually just a “simple, responsive template for building web mapping applications with Bootstrap 3, Leaflet and typeahead.js”.
Also written by yours truly, SpatialBB (or “spatially enabeled Backbone”) is an attempt to merge the MVC-capabilities of Backbone.js with the spatial capabilities of Leaflet. Also a work in (some state of) progress, but I kinda like the idea.
So, that was my list. What did I forget? Are there any gems that’s useful? Please point me in their direction!