ESM + CJS builds on the 3.x version

[philcockfield]

FIX for #49 , #52, #53

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Solution idea provided by conorfuller within #52

This is a Node 20/Next 14 based application and we are using a commonjs environment and am unable to switch easily to use ESM. Is it possible to add default exports to the package.json for increased module support? As has been done here for next/auth nextauthjs/next-auth@b1a8102

↑
NB: does not work.

Solution approach:

• alternative CJS + ESM typescript builder → [npm] pipeline
• dnt

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npm i [email protected].<latest>

Test sequence (CJS):

// filename: index.js
const fsc = require('file-system-cache');

node index.js

Test sequence (ESM):

// filename: index.js
import fsc from "file-system-cache";

const cache = fsc();
console.log(cache);

node index.js

[JessicaSachs]

Was 3.0.0-alpha.7 released from this PR? I'm having issues with dynamic requires happening in ESM (probably a dep of yours) and I'll report/write them up in the right place, but if it is this PR and you were planning on merging it, I wanted to give you a heads up.

[philcockfield]

Hey @JessicaSachs 👋 , this is the ESM (update) nightmare the world is facing. ESM is 10 years old now, and a proper standard - libraries forcing the upgrade like this is the right move IMO, but I also understand the frustration of it.

I hit this (personally, on other projects) a couple of years ago when high-quality libs started publishing ESM only version, and common-js broke, and at that point I bit the bullet and updated all my mono-repos to full ESM (no common-js).

This particular change on this repo came in via one of the Storybook maintainers, and has now inflicted this same problem on all the upstream dependents on this little lib.

I'm deciding what to do here...Node has been terrible, dragging it's feet on this ESM thing. But as an industry, we really do need to get off all the legacy "non-standards" now we have the one "actual", proper module standard for JS.

I'm low key thinking of refactoring this over into Deno, and just having a more modern, "standards based" runtime do all the legacy module bundling (aka. common-js).

--
PS: The prior 2.x version still works on common-js.
PPS: I see you work on "vitest" ← utterly beautiful test suite system!