[farkin88]

Interesting to get a library author's perspective. To be fair, you guys had to deal with the whole ecosystem shift: dual package hazards, CJS/ESM compatibility hell, tooling changes, etc so I can see how ESM would be the bigger story from your perspective.

[franciscop]

I'm a small-ish time author, but it was really painful for a while since we were all dual-publishing in CJS and ESM, which was a mess. At some point some prominent authors decided to go full-ESM, and basically many of us followed suit.

The fetch() change has been big only for the libraries that did need HTTP requests, otherwise it hasn't been such a huge change. Even in those it's been mostly removing some dependencies, which in a couple of cases resulted in me reducing the library size by 90%, but this is still Node.js where that isn't such a huge deal as it'd have been on the frontend.

Now there's an unresolved one, which is the Node.js streams vs WebStreams, and that is currently a HUGE mess. It's a complex topic on its own, but it's made a lot more complex by having two different streaming standards that are hard to match.

[farkin88]

What a dual-publishing nightmare. Someone had to break the stalemate first. 90% size reduction is solid even if Node bundle size isn't as critical. The streams thing sounds messy, though. Two incompatible streaming standards in the same runtime is bound to create headaches.

[bikeshaving]

The fact that CJS/ESM compatibility issues are going away indicates it was always a design choice and never a technical limitation (most CJS format code can consume ESM and vice versa). So much lost time to this problem.

[bakkoting]

It was neither a design choice nor a technical limitation. It was a big complicated thing which necessarily involved fiddly internal work and coordination between relatively isolated groups. It got done when someone (Joyee Cheung) actually made the fairly heroic effort to push through all of that.

Joyee has a nice post going into details. Reading this gives a much more accurate picture of why things do and don't happen in big projects like Node: https://joyeecheung.github.io/blog/2024/03/18/require-esm-in...

[tracker1]

There were some legitimate technical decisions, that said, imho, Node should have just stayed compatible with Babel's implementation and there would have been significantly less friction along the way. It was definitely a choice not to do so, for better and worse.

It's interesting to see how many ideas are being taken from Deno's implementations as Deno increases Node interoperability. I still like Deno more for most things.

[stevage]

I maintain a library also, and the shift to ESM was incredibly painful, because you still have to ship CJS, only now you have work out how to write the code in a way that can be bundled either way, can be tested, etc etc.

[8n4vidtmkvmk]

It was a pain, but rollup can export both if you write the source in esm. The part I find most annoying is exporting the typescript types. There's no tree-shaking for that!