TS defines __esModule of exports even if all imports are 'import type'

[anatawa12]

Bug (or bad specification) Report

If some doesn't have 'import', the tsc doesn't generate Object.defineProperty(exports, "__esModule", { value: true });.

import type looks standing for not generating import or code for module system in js but currently Object.defineProperty(exports, "__esModule", { value: true }); is generated.

🔎 Search Terms

In issues and on Google searched with '__esModule import type' and '__esModule generated even if import type'

🕗 Version & Regression Information

typescript: 4.1.3

• This is not a crash

⏯ Playground Link

Please ignore the compile error. I don't know what module can I use on the playground.

Playground link with relevant code

💻 Code

import type * as something from "<any path>";

{
  "compilerOptions": {
    "module": "commonjs",
    "noImplicitAny": true,
    "sourceMap": true,
    "outDir": "dist",
    "baseUrl": ".",
    "paths": {
      "*": ["node_modules/*"]
    },
    "target": "ES2019",
    "moduleResolution": "node"
  },
  "include": [
    "src/**/*"
  ]
}

🙁 Actual behavior

exports code below:

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });

🙂 Expected behavior

exports code below:

"use strict";

This can be a problem if I want to write ts without tools like WebPack.

[MartinJohns]

I'm pretty sure this is the same as #41513. By having an import statement you're making your file a module, and as a result you have a related exports statement in your compiled file. This behavior was introduced with 4.0, and the old behavior in TypeScript 3.9 is considered a bug.

[typescript-bot]

This issue has been marked as a 'Duplicate' and has seen no recent activity. It has been automatically closed for house-keeping purposes.