JavaScript private class methods with Snowpack

I use private JavaScript class methods in my front-end code and Snowpack for my development workflow.

Currently (as of v2.15.0-pre.5), Snowpack doesn't seem to play well with private class methods, i.e., the following fails to when building with snowpack build:

export class TestClass {
  #test() {
    console.log("testing...");
  }

  test() {
    this.#test();
  }
}

A repo to reproduce is here. After cloning, run:

npm install
npm run build

I've opened an issue with Snowpack, but apparently the problem lays in the integration with Rollup and the fix isn't a priority.

As far as I understand, to solve it we need:

• a custom Rollup plugin for Snowpack.
• such plugin should use acornInjectPlugins to inject acorn-private-methods.

I wonder if anyone could help with an example of this, before I dive deep into learning Rollup ecosystem?

Or maybe there's another way to make it work?

I'm now back to using _methodName instead of #methodName due to time constraints, but I plan to contribute a fix when time allows.

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