[v4] Publish @tailwindcss/postcss as ESM

[wesbos]

"@tailwindcss/postcss": "^4.0.0-alpha.15" is currently published as CJS, while "@tailwindcss/vite": "^4.0.0-alpha.15" is published as ESM.

Trying to use the postcss plugin inside a vite config file like this (with type: module set in package.json)

import tailwindcssPostCSS from '@tailwindcss/postcss'
import { defineConfig } from 'vite'
export default defineConfig({
  css: {
    postcss: {
      plugins: [tailwindcssPostCSS]
    },
  },
})

Causes this issue:

✘ [ERROR] Failed to resolve entry for package "@tailwindcss/postcss". The package may have incorrect main/module/exports specified in its package.json: No known conditions for "." specifier in "@tailwindcss/postcss" package [plugin externalize-deps]

node_modules/esbuild/lib/main.js:1374:27:
  1374 │         let result = await callback({
       ╵                            ^

a workaround currently is to use an external postcss.config.js file:

export default {
  plugins: {
    "@tailwindcss/postcss": {},
  },
};

[wesbos]

Ah - the exports are incorrect. This package is fine as CJS, as long as we fix the exports.

#13693

[RobinMalfait]

Hey!

This should be fixed by #13693, and will be available in the next release.