"open" structs

[eladb]

I am looking for a way to model this TypeScript idiom in Wing:

interface MyStruct {
  val1: str;
  val2: str;
  [key: string]: any;
}

The [key: string]: any indicates that the struct is "open".

An example where this would have been very useful is in the k8s.ApiObject winglib. Since Kubernetes API objects may have any schema, it would be really nice to be able to just pass them along like this:

new k8s.ApiObject(
  apiVersion: "v1",
  kind: "ConfigMap",
  metadata: k8s.ObjectMeta {
    name: "my-configmap",
  },
  data: {
    "hello": "world",
  },
);

Thoughts about syntax - maybe use spreads?

struct MyStruct {
  val1: str;
  val2: str;
  ...
}