Bug: __dirname is not defined when using sandbox.start({}) with ESM

[AlexKushnir1]

When using near-sandbox in a project configured for ESM (ECMAScript Modules), calling:

await sandbox.start({});

throws a runtime error:

ReferenceError: __dirname is not defined

This happens because __dirname is not available in ESM environments by default.

For now I see two ways:

-> Fully migration to ESM
Pros:

• No reliance on CommonJS globals;
• Simplifies long-term maintenance

Cons:

• Breaking change for CommonJS consumers

-> Dual output using conditional exports to let Node choose the appropriate file with dirName func
Pros:

• Backward-compatible
• Works for both CJS and ESM consumers

Cons:

• Complexity

I could work on it if get some insturctions.

[frol]

@AlexKushnir1 is there a simple fix only for the __dirname? If not, I would migrate to ESM and release a breaking change release. CJS users would be able to use the older version of near-sandbox-js while they migrate to ESM.

It would be amazing if you could work on it

[AlexKushnir1]

@frol I've been researching about this a lot and have not found some simple solution. However if we migrate to ESM we could to do something like this:

export const dirname =
  typeof __dirname !== "undefined"
    ? __dirname
    : path.dirname(url.fileURLToPath(import.meta.url));

and try to ship both ESM and commonJs builds. (if that`s really necessary)

With this breaking-change release, we could also better align this repository with near-sandbox-rs.