ajv - Ensure that given object structure matches structure of a custom type

I'm using ajv with TypeScript and have a custom type MyCustomType. When creating a validation schema I want to ensure that a specific property is of type MyCustomType. So ajv should validate its structure and decide whether this could be parsed to the given type.

I started with the following sample code ( and created a Codesandbox example for testing purposes )

import { AType } from "./AType"; // custom type
import { AnInterface } from "./AnInterface"; // custom interface
import Ajv from "ajv";

type MyComplexType = AType | AnInterface; // create a more complex type from the given imports

const ajvInstance = new Ajv();

const schema = {
  type: "object",
  properties: {
    myComplexType: { type: "string" } // value structure must match structure of  MyComplexType
  },
  required: ["myComplexType"],
  additionalProperties: false
};

const validate = ajvInstance.compile(schema);

const data = {
  myComplexType: {}
};

const isValid = validate(data);

if (isValid) {
  console.info("everything is fine");
} else {
  validate.errors?.forEach((error) => console.error(error.message));
}

Currently I don't know how to create a validation schema for the property myComplexType. I found some discussions

• Add instanceof property for type objects
• Creating a custom type
• Type keywords

but I don't think these will help because

• typeof just returns "object"
• instanceof won't work for types

So do I have to create a custom keyword ( as described here ) and write my own validation logic ( inspect the object structure ) or are there any things I can already use? How should I configure myComplexType?

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