[V6] `module` defaults is not `esnext`

[regseb]

🔎 Search Terms

"module", "default", "esnext", "v6"

🕗 Version & Regression Information

This changed between versions V5 and V6

⏯ Playground Link

This isn't an issue in Playground, because you're required to enter a value for the module.

https://www.typescriptlang.org/play/?#code/FASwtgDg9gTgLgAgGZSsmUwIEQDoD0KUuAVgM5QB22CA7iHABYIDeCcAnhAKYBcO5KjQC+AbmDAAxlQoAbbrllQA5gAoiASlFA

💻 Code

• package.json

  {
    "name": "testcase",
    "version": "1.0.0",
    "type": "module",
    "dependencies": {
      "typescript": "6.0.2"
    }
  }

• index.ts

  import foo from "./foo.json" with { type: "json" };
  
  console.log(foo);

1. npm install
2. npc tsc index.ts

🙁 Actual behavior

index.ts:1:30 - error TS2823: Import attributes are only supported when the '--module' option is set to 'esnext', 'node18', 'node20', 'nodenext', or 'preserve'.

1 import foo from "./foo.json" with { type: "json" };
                               ~~~~~~~~~~~~~~~~~~~~~

🙂 Expected behavior

No error because module defaults to esnext.

Additional information about the issue

In Announcing TypeScript 6.0, it says module defaults to esnext: Similarly, the new default module is esnext, acknowledging that ESM is now the dominant module format.

But in TSConfig Reference, it's CommonJS if target is ES5; ES6/ES2015 otherwise.

In the code, I don't think the default value is esnext. Otherwise, we wouldn't be getting the TS2823 error.

[mkantor]

I suspect that module is actually currently defaulting to es2022.

Since #63067, target defaults to ScriptTarget.LatestStandard, which is currently es2025, and that means the computed default for module is es2022.

Also, I get the same error message with npx tsc --module es2022 index.ts.

[mkantor]

This also made me notice that the documentation for the default value of target is currently wrong (at least the "ES5 otherwise" bit). This section also still mentions ES3 as an allowed target value, but that's no longer true.

[mkantor]

Re-reading that list item in the announcement post, I wonder if it's just a typo/editing mistake. Setting aside the incorrect information, the prose weirdly repeats itself ("module defaults to esnext: Similarly, the new default module is esnext"). I can't figure out what it's supposed to be saying, though.