Type declaration generation fails

[ayalon]

I try to build a nuxt module that uses some types of express in its interface. Unfortunatly this throws an error. It seems, that rollup tries to access the types declaration files written in typescript as a CommonJs file.

I have created a full reproduction scenario:

https://github.com/dulnan/nuxt-graphql-middleware/tree/feature/refactor-build

How to reproduce

git clone -b feature/refactor-build [email protected]:dulnan/nuxt-graphql-middleware.git
npm install
npm run build / npx unbuild

The following error occurs:

Error building /nuxt2-app/modules/nuxt-graphql-middleware: SyntaxError: Unexpected token (17:8) in /nuxt2-app/modules/nuxt-graphql-middleware/node_modules/@types/express-serve-static-core/index.d.ts
SyntaxError: Unexpected token (17:8) in /nuxt2-app/modules/nuxt-graphql-middleware/node_modules/@types/express-serve-static-core/index.d.ts
    at Parser.pp$5.raise (file:///nuxt2-app/modules/nuxt-graphql-middleware/node_modules/rollup/dist/es/shared/rollup.js:19407:13)
    at Parser.pp.unexpected (file:///nuxt2-app/modules/nuxt-graphql-middleware/node_modules/rollup/dist/es/shared/rollup.js:16732:8)
    at Parser.pp.semicolon (file:///nuxt2-app/modules/nuxt-graphql-middleware/node_modules/rollup/dist/es/shared/rollup.js:16709:64)
    at Parser.pp$1.parseExpressionStatement (file:///nuxt2-app/modules/nuxt-graphql-middleware/node_modules/rollup/dist/es/shared/rollup.js:17192:8)
    at Parser.pp$1.parseStatement (file:///nuxt2-app/modules/nuxt-graphql-middleware/node_modules/rollup/dist/es/shared/rollup.js:16925:24)
    at Parser.pp$1.parseTopLevel (file:///nuxt2-app/modules/nuxt-graphql-middleware/node_modules/rollup/dist/es/shared/rollup.js:16789:21)
    at Parser.parse (file:///nuxt2-app/modules/nuxt-graphql-middleware/node_modules/rollup/dist/es/shared/rollup.js:16570:15)
    at Function.parse (file:///nuxt2-app/modules/nuxt-graphql-middleware/node_modules/rollup/dist/es/shared/rollup.js:16612:35)
    at Graph.contextParse (file:///nuxt2-app/modules/nuxt-graphql-middleware/node_modules/rollup/dist/es/shared/rollup.js:22658:38)
    at tryParse (/nuxt2-app/modules/nuxt-graphql-middleware/node_modules/@rollup/plugin-commonjs/dist/index.js:26:12) {
  pos: 834,
  loc: {
    column: 8,
    file: '/nuxt2-app/modules/nuxt-graphql-middleware/node_modules/@types/express-serve-static-core/index.d.ts',
    line: 17
  },
  raisedAt: 840,
  frame: '15: /// <reference types="node" />\n' +
    '16: \n' +
    '17: declare global {\n' +
    '            ^\n' +
    '18:     namespace Express {\n' +
    '19:         // These open interfaces may be extended in an application-specific manner via declaration merging.',
  id: '/nuxt2-app/modules/nuxt-graphql-middleware/node_modules/@types/express-serve-static-core/index.d.ts',
  hook: 'transform',
  code: 'PLUGIN_ERROR',
  plugin: 'commonjs',
  watchFiles: [
    '/nuxt2-app/modules/nuxt-graphql-middleware/src/module.ts',
    '/nuxt2-app/modules/nuxt-graphql-middleware/src/serverMiddleware.ts',
    '/nuxt2-app/modules/nuxt-graphql-middleware/src/codegen.ts',
    '/nuxt2-app/modules/nuxt-graphql-middleware/src/runtime/middlewarePlugin.ts',
    '/nuxt2-app/modules/nuxt-graphql-middleware/node_modules/@types/express-serve-static-core/index.d.ts'
  ]
}