Use 6to5 instead, it does the job and is fantastic.
> node6 es6app.js> node6 -e "{let test = function *() {yield 3; yield 4}; let t = test(); console.log(t.next().value, t.next().value);}"
3 4// mymodule.jslettest=function*(){yield3;yield4};module.exports=test()// index.jsrequire('node6')(__dirname)// enable node6 for this module (but not inner node_modules)vart=require('./mymodule')console.log(t.next().value)// 3console.log(t.next().value)// 4