stream.js : stream.js is a tiny stand-alone Javascript library that unlocks a new data structure for you: streams.
Logerr : Experimenting with window.onerror, trying to make JavaScript debugging easy.
What does it do?
Provides JavaScript error details in a readable format. ...
TraceKit : Not all browsers support stack traces on error objects, but TraceKit squeezes out as much useful information as possible and normalizes it.
ProseMirror : In-browser structured text editing component. A toolkit for building rich-text editors on the web.