Build: JS interop does not appear to work in tests with build_web_compilers 2.0.0

[corwinsheahan-wf]

Hi there!

We recently began upgrading some of our packages to use build_web_compilers 2.0.0. Unfortunately, we noticed that tests seemed to have issues calling functions from react.js. I was able to create a reduced test case that appears to show that js interop is not working properly in tests with build_web_compilers 2.0.0, which you can find here.

In that package, if you switch the deps to use build_web_compilers 1.x, the test will pass, but on build_web_compilers 2.0.0, the test will fail because it doesn't properly call the js method. I've also verified via using the --pause-after-load flag that the some.js file can be loaded successfully in the browser via the path specified in the test html.

This is on Dart 2.3.0. Thanks for the help!

[jakemac53]

Duplicate of https://github.com/dart-lang/sdk/issues/36912, note that it is cross-module JS-interop that doesn't work (that is, invoking a function marked as @JS in another library. You can work around the issue by making the actual @JS annotated function be private and making a regular function in the library that delegates to it. Essentially, this:

@JS()
external _foo();

foo() => _foo();

[jakemac53]

Even though this is a duplicate I will leave it open for now I think so it is easier to find and we don't get a ton more duplicates :).

[jakemac53]

Note that the core issue in the sdk is resolved here, so the next release should have a fix (stable or dev).

[corwinsheahan-wf]

Thanks @jakemac53!

[natebosch]

Closing since this should be resolved with the latest SDKs