type.ts

// schema validation
import { z } from "zod"

enum Risk {
    Low,
    Medium,
    High,
}

const _CalculateRiskProfile = (age: _Age): Risk => (__Age.parse(age) < 60 ? Risk.Low : Risk.Medium)
const __Age = z.number().refine((age: number) => 0 <= age && age < 120)
type _Age = z.infer<typeof __Age>

console.log(_CalculateRiskProfile(70)) // 1
console.log(_CalculateRiskProfile(9999)) // Error