key paths for recursive nested types

type Schema = {
  name: string,
  description: string,
  type: "string" | "number" | "boolean" | "array" | "object",
  enum?: string[],
  properties?: Schema[],
  items?: Omit<Schema, "name" | "description">,
}

const schema: z.ZodType<Schema> = z.object({
  name: z.string(),
  description: z.string(),
  type: z.union([z.literal("string"), z.literal("number"), z.literal("boolean"), z.literal("array"), z.literal("object")]),
  enum: z.array(z.string()).optional(),
  properties: z.array(z.lazy(() => schema)).optional(),
  items: z.lazy(() => schema).optional(),
})

type Keypath<T> = T extends { properties: Schema[] }
  ? { [K in keyof T['properties']]: `properties.${K}` | Keypath<T['properties'][K]> }[keyof T['properties']]
  : T extends { items: Omit<Schema, "name" | "description"> }
  ? `items.${number}` | Keypath<T['items']>
  : never;

const formSchemaKeyPath = z.string().regex(/^(functions)((\.[0-9]+)(\.(properties|items)))*/)