Post

I get the desire for ESM for things like tree shaking (though I'd like to see some numbers on impact here). I get the nicer syntax. But, unbundled ESM takes about 2x as long as CJS to load in my tests (can show if desired). If your users aren't bundling ESM opts them in to big a load-time perf hit.

This more or less confirms what @jarredsumner.com observed almost 2 years ago. bun.sh/blog/commonj...

CommonJS is fine, its not gonna go anywhere but its legacy. The effort needs to go into making esm better and working with APM. The answer is not "use commonjs", but work on the spec

I believe they should switch to esm anyways and push for the improvements in the right forum

Why not both push for improvements and allow users to prefer performance at the same time?

Because standardization favors improvement. If we all use the same thing its easier to unite and make that thing better. CommonJS should be marked as legacy and it's something I plan to do. Basically say, we switch our efforts to esm and make it first class citizen. Don't use it for new projects.