Cannot use `cdktf.Lazy.stringValue` in Wing

I tried this:

bring "cdktf" as cdktf;

let token = cdktf.Lazy.stringValue({
  produce: () => {
    if this.bundleHash == nil {
      throw "bundleHash was not set";
    }
    return this.bundleHash;
  }
});

This happened:

Multiple errors:

Expected type to be "IStringProducer", but got "Json" instead

"preflight (): unknown" is not a legal JSON value

I expected this:

I expected to have some way to create an object that satisfies the IStringProducer in preflight without needing to define a class. It's possible I could define a new preflight class which implements the IStringProducer interface, instantiate the class, and pass it to Lazy.stringValue, but that's not really desirable here since I want an object that's not a construct, and by default any preflight class is a construct.

I feel like the ideal solution would be to allow the Wing code above where an anonymous object is created. Optionally, the user should be able to provide the interface name before the object literal, to write code like this:

let producer = cdktf.IStringProducer {
  produce: () => {
    if this.bundleHash == nil {
      throw "bundleHash was not set";
    }
    return this.bundleHash;
  }
};
let token = cdktf.Lazy.stringValue(producer);

Is there a workaround?

You can create an extern like this:

class Util {
  pub static extern "./function-aws.ts" asStringToken(producer: (): str?): str;
}

With this implementation:

import { Lazy } from "cdktf";

import types from "./util.extern";

export const asStringToken: types["asStringToken"] = (producer) => {
  return Lazy.stringValue({ produce: producer });
};

And call it like this:

Util.asStringToken(() => { return "implementation" });

Anything else?

No response

Wing Version

0.82.5

Node.js Version

20.12.2

Platform(s)

No response

Community Notes

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Start by tracing the Wing compiler path for object literals passed to interface-typed parameters, using the IStringProducer argument in cdktf.Lazy.stringValue as the reproduction. Compare the current Json and illegal JSON errors with the requested anonymous interface object syntax; done means the example type-checks without requiring a preflight class.