Named exports for Node ESM for coffeescript package

[GeoffreyBooth]

When writing ES module code in Node, the following doesn’t currently work:

import { compile } from 'coffeescript';

This is because coffeescript is a CommonJS package that exports a single object (module.exports = CoffeeScript) and Node’s “best guess” algorithm for trying to detect named exports of CommonJS packages can’t find CoffeeScript’s exports. Currently only import CoffeeScript from 'coffeescript' works.

This PR simply adds several lines that explicitly define the named exports, which enables code like the first example to work. cc @guybedford

There are no tests for this, because the only way to currently run ESM code in Node from a CommonJS context is to either use an experimental API that’s moribund and likely to significantly change whenever it gets picked up again, or to spawn a child process of Node which is a bit too resource-intensive for our test suite. This code is extremely low risk, though, and doesn’t strike me as needing tests.

[edemaine]

FWIW, I just tested this locally, with npm link and the following code:

import CS, {compile} from 'coffeescript'
console.log(CS, compile, CS.compile === compile)

Confirmed that this additional functionality doesn't seem to mess up regular import, or require. Funny that it's necessary, but x.y = x.y shouldn't hurt. 🙂