Potential failure in static initializer when bundling

[pfumagalli]

When bundling is enabled, class definitions are rewritten as variable assignment + anonymous class, and that might create some issues with static initializers.

For example, given this code in testme.js:

export class MyTest {
  static {
    MyTest.prototype.foo = 'bar'
  }
}

When not bundling (e.g. esbuild --format="esm" testme.js, the code gets transpiled as follows:

class MyTest {
  static {
    MyTest.prototype.foo = "bar";
  }
}
export {
  MyTest
};

In this case the static initializer works without any issues. On the other hand, when bundling (e.g. esbuild --format="esm" --bundle testme.js) the class definition gets rewritten this way:

// testme.js
var MyTest = class {
  static {
    MyTest.prototype.foo = "bar";
  }
};
export {
  MyTest
};

In this second case, the static initializer fails as MyTest is not defined when running the static initializer.

I think that preserving the class name in the variable assignment should be "ok" (there doesn't seem to be any side effect), and this seems to work (OtherTest is defined, MyTest is not):

var OtherTest = class MyTest {
  static {
    MyTest.prototype.foo = 'bar'
  }
}

// ... here `MyTest` is not defined...

export {
  OtherTest
}

But I'm not 100% sure whether this would be a good solution or there might be some alternatives...

Note, yes, I know we can use this to refer to the class in the static initializer, but I don't have control over the library's source, unfortunately!

[modderme123]

I just ran into a similar issue with @angular/core as well, and noticed that this is probably a duplicate of #2950