typed_wrapper.ts

enum Gender {
    MALE,
    FEMALE,
    UNKNOWN,
}

type Person = {
    name: string;
    age: number;
    verified: boolean;
    gender: Gender;
    children: Person[];
    useless: null;
    someTuple: [string, number];
};

type FormModel = {
    entries: Person[];
    main: Person;
}

type TypedPathGenerator = {
    getPath(): string;
}

type TypedArrayWrapper<E, T extends E[]> = TypedPathGenerator & {
    [index: number]: TypedPathWrapper<E>;
}

type Primitives = string | number | boolean | null | undefined;

type TypedValueWrapper<T extends Primitives> = TypedPathGenerator;

type TypedPathWrapper<T extends Object> = TypedPathGenerator & {
    [K in keyof T]: T[K] extends (infer E)[] ? TypedArrayWrapper<E, T[K]> : T[K] extends Primitives ? TypedValueWrapper<T[K]> : TypedPathWrapper<T[K]>;
};

type FormXYPath = TypedPathWrapper<FormModel>;

function foo(x: FormXYPath) {
    x.entries[0].age.getPath();

    x.main.gender.getPath();
    x.main.children[1].gender.getPath();
    x.main.gender.getPath();
    x.main.verified.getPath();

    x.main.useless.getPath();

    x.main.someTuple.getPath();

    x.main.getPath();
}