Just as we can do:

# app.coffee
require 'coffeescript/register'
{ slice } = require './pizza.coffee'

or

// app.js
require('babel/register');
const { slice } = require('./pizza.js');

we should be able to achieve the equivalent in ESM, e.g. import a CoffeeScript file or import a JavaScript file that requires transpilation. References: CoffeeScript register, babel-register.

Use case 4. Related to #82.