The es6-shim library monkey-patches a JavaScript context to contain all ECMAScript 6 (Harmony) methods that can be faithfully emulated with a legacy JavaScript engine.

The es6-sham part tries to complete the picture as best as possible, but for those methods the result is not as close and mostly intends to avoid runtime errors : in many cases it might just silently fail.

Node.js is an event-based server-side JavaScript engine.