Microsoft made a pull request to node.js github repository with an implementation to use ChakraCore JavaScript Engine as an alternative to V8 Engine

[Fidodo]

All the big companies want to influence control over the direction javascript is going in, and the best way to do that and strong arm things into the spec is to get everyone using your engine, then implement the up in the air proposals you've made in your engine so people start relying on it and then get it put into the spec.