why is there a package.json export for package.json?

[dagda1]

Hi,

Apologies if this is the wrong place to ask but I wonder if it would be possible to explain why package.json is included in the exports?

{
  "exports": {
    ".": "./dist/index.js",
    "./*": "./dist/components/*/index.js",
    "./styles": "./dist/styles/index.css",
    "./styles/*": "./dist/styles/*/index.css",
    "./package.json": "./package.json"
  },
}

[ctjlewis]

So, weirdly, there are bundlers that would throw when trying to interop between ESM and CJS if package.json was not manually specified this way in conditional exports. This field is meant to prevent that from happening at all. I think the last context I saw it in was React Native with Metro as the bundler.

This will also allow for import pkgJson from "my-package/package.json" assert { type: "json" } out of the box when Node supports it.

See:

• Not support node v17 vercel/next.js#31514
• Special treatment for package.json resolution and exports? nodejs/node#33460
• package.json is not defined by "exports" uuidjs/uuid#444
• fix: export package.json required by react-native and bundlers uuidjs/uuid#449
• Importing error in React Native starting from nanoevents 3.0 version ai/nanoevents#44 (comment)
• CommonJS Support jaredh159/tailwind-react-native-classnames#93
• fix: export package.json ianprime0509/pitchy#108
• [package.json] Add ./package.json to exports moment/luxon#1239
• Added "./package.json" to "exports" field magiclabs/magic-js#273
• Manually export package.json to support introspective tools RubenVerborgh/AsyncIterator#34