In OpenAPI 3, a schema like:

    AnyValues:
      description: An object whose property values can be of any type
      type: object
      additionalProperties: true

Should be equivalent to a typescript type like:

type AnyValues = {
    [key: string]: any
};

However what openapi-typescript-codegen actually generates is a type like this:

type AnyValues = {
};

That is, an object with no properties.

Additionally, OpenAPI allows combining additionalProperties: true with explicit property definitions. So an OpenAPI schema like this:

SomeType:
    type: object
    required: [name]
    properties:
        name:
            type: string
    additionalProperties: true

Should result in a typescript type like:

type SomeType = {
    name: string,
    [key: string]: any
};

but in fact it results in:

type SomeType = {
    name: string
};

Desired result: additionalProperties: true in an object schema should result in a [key: string]: any property in the corresponding typescript type.