v4 fails to load in @web/test-runner

[tpluscode]

I started receiving this error when trying to run my tests:

Could not resolve import "stream"

I traced this to a dependency which now uses v4 of readable-stream. In the module lib/ours/index.js there is a const Stream = require('stream')

Why import the built-in?

[mcollina]

so that instanceof Stream would work. But maybe we should soft-detect if that's available and fall back to our implementation.

[mcollina]

Would you like to send a PR?

[tpluscode]

Happy to, although I'm not sure what the fix would entail. How would you "soft-detect" in a way which avoid the import?

[kanongil]

I expect you can surround the require in try/catch:

try {
    var Stream = require('stre' + 'am');
}
catch (err) {}

This will make the Stream value undefined both if require is undefined and if it fails to find the 'stream' module.

Additionally, I changed the import to a "computed" value so that tooling will leave it alone.

[tpluscode]

To be honest, I'm at a loss here. I think I will close the issue for now as it likely exposes some other problem with rollup or @web/test-runner which not necessarily caused by readable-stream