Type Alias Keypath<S>

Keypath: S extends `${infer K}.${infer Rest}`
    ? K extends string
        ? Rest extends string ? `${K}.${Keypath<Rest>}` : never
        : never
    : S extends `${infer K}[${infer Index}]${infer Rest}`
        ? K extends string
            ? Index extends `"${string}"`
            | `${number}`
            | `'${string}'`
                ? Rest extends ""
                    ? `${K}[${Index}]`
                    : Rest extends `.${infer RestPath}`
                        ? `${K}[${Index}].${Keypath<RestPath>}`
                        : Rest extends `[${infer NextIndex}]${infer RestPath}`
                            ? `${K}[${Index}][${NextIndex}]${RestPath extends ""
                                ? ""
                                : Keypath<RestPath>}`
                            : never
                : never
            : never
        : S