• Rollup Plugin Name: @rollup/plugin-node-resolve
• Rollup Plugin Version: 15.0.1
• Rollup Version: 3.20.2
• Operating System (or Browser): Ubuntu 20.04, Chrome 111
• Node Version: 18.14.1
• Link to reproduction: https://github.com/felixcatto/vite-test/tree/bug

Expected Behavior

When i import '.ts' file from '.tsx' file, and specify '.js' extension, it should be imported.

Actual Behavior

I get error

Additional Information

ES modules want that we add file extensions to all files https://nodejs.org/api/esm.html#mandatory-file-extensions
But Typescript doesn't like '.ts', '.tsx', it want '.js', '.jsx', '.mjs', ...

But if i import utils.js, when actual files have different extension i got following error

index.tsx

import { x } from './utils.js';

utils.ts

export const x = '';

index.tsx  'import'  utils.ts    # error
index.ts   'import'  utils.tsx   # error
index.js   'import'  utils.tsx   # error
index.ts   'import'  utils.ts    # works
index.tsx  'import'  utils.tsx   # works

In webpack i can define resolveextensionalias https://webpack.js.org/configuration/resolve/#resolveextensionalias

In rollup nodeResolve extensions option seems combines webpack extensionalias & extensions options. But only partially. It only works if all extensions matches, i.e. all files have '.tsx'