Kill CJS

[brillout]

Clear and concise description of the problem

CJS is alive.

Suggested solution

Kill it. By transitioning following tools to ESM-only.

• Vite
• Nuxt @pi0
• Next.js @rauchg

This will effectively force the entire ecosystem to transition to ESM.

Note that old CJS packages can stay as-is and don't need any changes for the forseeable future. (But if they update one of their dependencies then they'll be forced to switch to ESM.)

Let's rip the band-aid off :-).

Explanation of why this will work: #4340 (comment).

Alternative

None 😉.

Additional context

No response

Validations

• Follow our Code of Conduct
• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that request the same feature to avoid creating a duplicate.

[brillout]

@patak-js

I would also like a pure ESM world, but it is indeed painful. We can't update several deps because of this in Vite. And Jest is playing against us segfaulting in CI because of ESM issues right now... I hope we can switch away from it soon

This ticket solves that problem.

[pi0]

You can put a ✅ on Nuxt3. All packages are in ESM only format since nuxt/framework#539.

BTW we have to keep supporting cjs deps for time being until ecosystem is more prepared (notably Jest, Typescript and Node.js for under-the-flag features) :)

[Shinigami92]

Vite 3.0?

[Shinigami92]

Vite 4.0? 😅

We need a smooth transition from cjs to esm.
We should not force the community to switch right now, cause this would break many things.

[aladdin-add]

it would be good to support esm plugins in vite 3.0, so the ecosystem can gradually move to esm.

we can imagine dropping cjs support at some point (vite v4/v5...) when the community is ready to accept. :)

[Shinigami92]

it would be good to support esm plugins in vite 3.0, so the ecosystem can gradually move to esm.

we can imagine dropping cjs support at some point (vite v4/v5...) when the community is ready to accept. :)

Feel free to open a PR that supports both types of plugins: cjs and esm

[benmccann]

We should not force the community to switch right now, cause this would break many things.

I'm curious what you anticipate would be problematic. We've been supporting ESM-only for SvelteKit and have found it to be fairly smooth overall.

[patak-dev]

In Vite v3, Vite will migrate to ESM (with CJS compat), the SSR build will also be ESM by default (with the current CJS SSR build as opt-in), and Vitest is used instead of Jest:

• Use ESM for SSR builds #8150
• feat!: migrate to ESM #8178
• test: migrate to vitest #8076

We can close this issue for the moment to avoid having a generic request for a long time in the tracker. We think that going ESM-only isn't the best for the ecosystem right now, but Vite will make big steps towards that future in v3.

[brillout]

I believe we should drop CJS support already in Vite 3, see #8432.