The compiler is the bundler is the runtime. The reason it’s such a problem on Node is because the tools are separate and often conceptually at odds.
I imagine that's quite rare, because such a package would only be imported or required for its side effects; and because that package cannot import or require any others, could you safely just assume that if it was `require()`ed use CJS, and if it was `import`ed, use ESM?
The risk for Bun's adoption is that they're wrong, of course.
The risk for Node's usage is that they're right, and library authors begin urging users to use Bun because it's 100x easier than making a useful library with Node. (This will happen very slowly, but things that happen very slowly can start happening all at once very quickly.)
Such as? If you could provide 5-10 of your many examples and why you think that Bun's approach doesn't solve them it would be very helpful.
Possibly the most devious nuance is whether the spec's appendix B applies, which affects whether html comment syntax is valid (yes, this is a thing). The html comment token can therefore be parsed either as a comment or as a series of operators depending on the grammar being used.
Effectively, this means it's possible to craft a program that does different things in CJS vs ESM mode.