My advice is bite the bullet and just write a JSON Schema for the interface and use ajv[1] to check it. Keep the interface, the JSON Schema, and the validator f

My advice is bite the bullet and just write a JSON Schema for the interface and use ajv[1] to check it. Keep the interface, the JSON Schema, and the validator function (which should be a type guard[2] to take full advantage of TypeScript) in the same module for easier maintenance. [1] https://github.com/epoberezkin/ajv https://github.com/epoberezkin/ajv [2] https://www.typescriptlang.org/docs/handbook/advanced-types.html#user-defined-type-guards https://www.typescriptlang.org/docs/handbook/advanced-types....