fix(libConfig): import default in CJS build

[ShGKme]

How to test

1. Use chore: Bump @nextcloud/vue + @nextcloud/dialogs + @nextcloud/calendar-availability-vue nextcloud/server#40692 with the latest @nextcloud/vue
2. Run npm test (or better just npx jest CalDavSetting for a single test)
3. See [Vue warn]: Failed to mount component: template or render function not defined

A problem

By default,

Rollup assumes that the required value should be treated as the default export of the imported module, just like when importing CommonJS from an ES module context in NodeJS. This is different from the default behavior in many tools like Babel or TS.

As a result, when a CJS lib built with this config is used with such tooling, external dependencies are imported as an object with a default property.

// Inside NcComponent.cjs
const icon = require('vue-material-design-icons/Icon.vue)

// Imports as

{
  default: {
    name: 'Icon',
    render: () => {},
  }
}

// Instead of

{
  name: 'Icon',
  render: () => {},
}

Proposal

interop: auto adds a hack with __esModule to help tools interpret it.

Alternative

Formally __esModule is a hack. Supported by all the tolling but still.

interop: compat also works checking how the module was imported

See: https://rollupjs.org/configuration-options/#output-interop

P.S.

I'm not sure it fixes all the issues with the new CJS built. Checking...

[codecov]

Codecov Report

Merging #35 (b108a87) into main (28a71a8) will increase coverage by 0.03%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main      #35      +/-   ##
==========================================
+ Coverage   80.22%   80.26%   +0.03%     
==========================================
  Files           8        8              
  Lines         536      537       +1     
  Branches       32       32              
==========================================
+ Hits          430      431       +1     
  Misses         74       74              
  Partials       32       32              

Files	Coverage Δ
lib/libConfig.ts	88.81% <100.00%> (+0.07%)	⬆️