stop-iteration-iterator 
Firefox 17-26 iterators throw a StopIteration object to indicate "done". This normalizes it.
Usage
var stopIterationIterator = require('stop-iteration-iterator');
var s = new Set([1, 2]);
var iterator = stopIterationIterator(s.keys());
iterator.next(); // { done: false, value: 1 }
Tests
Simply clone the repo, npm install
, and run npm test