The problem with the CJS-ES6 gap

cjs-es6-modules.js

// ES6 exports

export var foo = 1
export var bar = true

// CJS analog

module.exports = {
  foo: 1,
  bar: true
}

// Importing all exports from the above ES6 module

import * as mod from 'module'

// I think it can be argued that if you're allowing CJS to be imported using ES6 syntax, then
// the above CJS module could also be imported using:

import * as mod from 'module'

// However, if you allow the above, then it in turn also means you can do this:

// CJS module

module.exports = function foo() {}

// Importing...

import * as func from 'module'

I heavily recommend people use import mydefault from 'foo' over * when doing interop with CJS.