Buble + little bit of babel for your esnext tests
npm install buba 



The usecase would be transpiling es* source code with Bublé and have tests match as well. An alternative to using babel-register
The primary transformer here is Bublé we only use Babel for support with module import/exports.
``sh`
npm install buba --save-dev
CLI
`sh`
buba -i input.js -o output.jsor with a directory
buba -i src/ -o lib/to enable sourceMaps
buba -i input.js -o output.js -s
API Usage
`js
import { transformFile } from 'buba'
const { code, map } = transformFile('input.js', {
buble: {} // buble options
babel: {} // babel options
})
`
sh
mocha --require buba/register tests/*/.js
or
tape --require buba/register tests/*/.js
`With
mocha you can also provide buba within the mocha.opts config file:`sh
--require buba/register
--reporter spec
--ui bdd
`Currently we only plan to use Babel for modules but you can add support for something like generators by adding a
.babelrc file.API Usage
Just make sure that
buba is the 1st thing you require`js
require('buba/register')
const prelude = require('./prelude') // prelude has import/export, arrow functions, etc
``