sandboxed-module error with transitive ES6 deps

bar-es6.js

export default 'bar';

bar.js

module.exports = 'bar';

foo.js

import bar from './bar';

console.log('foo: bar:', bar);

export default 'foo';

main.js

import traceurAPI from 'traceur/src/node/api.js';
import SandboxedModule from 'sandboxed-module';

var es6 = source => {
    var compiler = new traceurAPI.NodeCompiler({ modules: 'commonjs' });
    return compiler.compile(source);
};

// ES6 modules translate to a CJS module with a default property
var sandboxEs6Require = (moduleId, options) => {
    let defaultOptions = { sourceTransformers: { es6 } };
    return SandboxedModule.require(
        moduleId,
        Object.assign({}, defaultOptions, options)).default;
};

var foo = sandboxEs6Require('./foo', { requires: { http: 'mocked http' } });

console.log('main: foo:', foo);

package.json

{
  "name": "sandbox-test",
  "version": "0.0.0",
  "dependencies": {
    "sandboxed-module": "^1.0.2"
  },
  "devDependencies": {
    "traceur": "0.0.72",
    "traceur-source-maps": "^1.0.5"
  }
}

traceur-runner.js

'use strict';

var traceur = require('traceur');
require('traceur-source-maps').install(traceur);
var path = require('path');

traceur.require.makeDefault(function (modulePath) {
    var isDependency = modulePath.indexOf('node_modules') !== -1;

    return ! isDependency;
});

require(path.resolve(process.cwd(), process.argv[2]));