importing mjs fails in node

[laat]

package.json

{
  "type": "module",
  "devDependencies": {
    "openapi3-ts": "^4.1.1"
  }
}

app.mjs

import x from 'openapi3-ts/oas31';
const builder = new x.OpenApiBuilder();
console.log(builder.rootDoc);

it fails to import when running node app.mjs

(node:59840) Warning: To load an ES module, set "type": "module" in the package.json or use the .mjs extension.
(Use `node --trace-warnings ...` to show where the warning was created)
.pnpm/openapi3-ts@4.1.1/node_modules/openapi3-ts/dist/mjs/oas31.js:1
export * from './dsl/openapi-builder31';
^^^^^^

SyntaxError: Unexpected token 'export'
    at internalCompileFunction (node:internal/vm:73:18)
    at wrapSafe (node:internal/modules/cjs/loader:1195:20)
    at Module._compile (node:internal/modules/cjs/loader:1239:27)
    at Module._extensions..js (node:internal/modules/cjs/loader:1329:10)
    at Module.load (node:internal/modules/cjs/loader:1133:32)
    at Module._load (node:internal/modules/cjs/loader:972:12)
    at ModuleWrap.<anonymous> (node:internal/modules/esm/translators:165:29)
    at ModuleJob.run (node:internal/modules/esm/module_job:193:25)

Node.js v19.9.0

It's probably because the published package.json does not have "type": "module", or that the published files does not end with ".mjs"

[koooge]

Since cjs would not work with type module, the file ext should be .mjs. Also, tsc doesn't seem to be able to change file ext. https://github.com/microsoft/TypeScript/issues/49462

[laat]

I'm pretty happy with tsup

tsup src --format cjs,esm --clean --sourcemap instead of or in conjunction with tsc

[koooge]

That looks cool. vite is also another option since openapi3-ts depends on vitest. I don't have a special opinion.