(() => {
  class Data {
    x = 1;
    y = "two";
    nested = { z: [3] };
  }

  // A class name that is not a valid identifier renders quoted, as a key
  // does; a class with no name renders under the `<anonymous>` marker.
  class Renamed {
    static name = "Not a proper identifier";
    x = 1;
  }
  class WithNewline {
    static name = "a\nb";
  }
  return {
    data: new Data(),
    empty: new (class Empty {})(),
    "name not an identifier": new Renamed(),
    "name with a newline": new WithNewline(),
  };
})()

--

data:
/Data(x:1,y:"two",nested:{z:[3]})
/Data(
  x: 1,
  y: "two",
  nested: {
    z: [
      3
    ]
  }
)
{
  "/Data": {
    x: 1,
    y: "two",
    nested: {
      z: [
        3
      ]
    }
  }
}

empty:
/Empty(...)
/Empty(...)
{
  "/Empty": "/..."
}

name not an identifier:
/"Not a proper identifier"(x:1)
/"Not a proper identifier"(
  x: 1
)
{
  "/Not a proper identifier": {
    x: 1
  }
}

name with a newline:
/"a\nb"(...)
/"a\nb"(...)
{
  "/a\nb": "/..."
}