A locally build NPM package - generated by the openapi-generator - does not seem to export the API, although it's available

Question

I created a REST service interface definition with one very simple GET endpoint using OpenAPI 3.
(There is a minified version of that interface in the spoiler.)

{"openapi":"3.0.3","info":{"title":"Identity Cache API Definition","version":"1.0"},"tags":[{"name":"identity-cache"}],"paths":{"/{identityId}/data":{"get":{"tags":["identity-cache"],"summary":"Returns data.","operationId":"getIdentityData","parameters":[{"name":"identityId","in":"path","description":"The identity ID.","required":true,"schema":{"type":"string"}}],"responses":{"200":{"description":"The identity data.","content":{"application/json":{"schema":{"$ref":"#/components/schemas/IdentityData"}}}}}}}},"components":{"schemas":{"IdentityData":{"type":"object","required":["identityId"],"properties":{"identityId":{"type":"string"}}}}}}

Then I generated the typescript-fetch source code with the openapi-generator:

openapi-generator-cli generate -i ../identity-cache-api.yaml -o ./ -g typescript-fetch \
    --additional-properties=supportsES6=true,typescriptThreePlus=true,npmVersion=1.0.0,npmName=identity-cache-fetch

After that I built the generated npm package with Node.js v14.7.0 using npm:

npm run build

And finally I added the built package locally to my project with npm install. Here is the added line in the package.json:

"identity-cache-fetch": "file:../identity-cache-npm-package",

Seems good, Visual Studio Code recognizes the new package and let me use it:

import { Configuration, IdentityCacheApi } from "identity-cache-fetch";

const identityCacheApi = new IdentityCacheApi(new Configuration({ basePath: import.meta.env.VITE_BACKEND_URL }));

However the build fails with: vite build
This error arises:

[INFO] error during build:
[INFO] Error: 'IdentityCacheApi' is not exported by ../identity-cache-npm-package/dist/index.js, imported by src/services/service.ts
[INFO]     at error (../frontend/node_modules/rollup/dist/shared/rollup.js:160:30)
[INFO]     at Module.error (../frontend/node_modules/rollup/dist/shared/rollup.js:12438:16)
[INFO]     at Module.traceVariable (../frontend/node_modules/rollup/dist/shared/rollup.js:12808:29)
[INFO]     at ModuleScope.findVariable (../frontend/node_modules/rollup/dist/shared/rollup.js:11601:39)
[INFO]     at Identifier.bind (../frontend/node_modules/rollup/dist/shared/rollup.js:6479:40)
[INFO]     at NewExpression.bind (../frontend/node_modules/rollup/dist/shared/rollup.js:5087:23)
[INFO]     at VariableDeclarator.bind (../frontend/node_modules/rollup/dist/shared/rollup.js:5087:23)
[INFO]     at VariableDeclaration.bind (../frontend/node_modules/rollup/dist/shared/rollup.js:5083:31)
[INFO]     at Program.bind (../frontend/node_modules/rollup/dist/shared/rollup.js:5083:31)
[INFO]     at Module.bindReferences (../frontend/node_modules/rollup/dist/shared/rollup.js:12434:18)
[INFO] npm ERR! code ELIFECYCLE
[INFO] npm ERR! errno 1

The index.js seems good. For simplicity, I'm only posting the TypeScript code of the uncompiled index.ts.

/* tslint:disable */
/* eslint-disable */
export * from './runtime';
export * from './apis';
export * from './models';

What am I missing?
Or is it a bug in the openapi-generator or vite?

Answer 1

It's an rollup issue.

By adding an ESM (ECMAScript Module) to the generated code the project finally builds.