Does not find .mts file when doing extensionless import and Bundler

[wmertens]

🔎 Search Terms

mts bundler

🕗 Version & Regression Information

• This is the behavior in every version I tried, and I reviewed the FAQ for entries about Bundler

⏯ Playground Link

cannot test modulerResolution in the playground

💻 Code

tsconfig.json

  moduleResolution: "Bundler"

file.mts

export const hi = 1

file2.mts

import {hi} from './file'

🙁 Actual behavior

fails to find ./file

🙂 Expected behavior

should resolve just like a bundler, so it should find the .mts file

Additional information about the issue

No response

[MartinJohns]

https://www.typescriptlang.org/docs/handbook/modules/reference.html#extensionless-relative-paths

TypeScript currently never supports omitting a .mjs/.mts or .cjs/.cts file extension, even though some runtimes and bundlers do.

---

file.mts

export hi = 1

That's not valid code.

[wmertens]

@MartinJohns from that same url:

In some cases, the runtime or bundler allows omitting a .js file extension from a relative path. TypeScript supports this behavior where the moduleResolution setting and the context indicate that the runtime or bundler supports it:

With moduleResolution: "Bundler", you can import these extensions extensionless: js ts jsx tsx cjs mjs. Bundlers also allow mts and cts.

I fixed the invalid code