Functional TypeScript: Either vs Validation

functional-typescript-either-vs-validation-05.ts

import { traverse } from 'fp-ts/lib/Array'

const checkGenderV = (p: Person) => (p.gender !== 'Male' ? failure(['Men only']) : validation.of(p))

function costToEnter3(p: Person): Validation<Errors, number> {
  const price = (p: Person) => p.age + 1.5

  const checks = [checkAgeV, checkClothesV, checkSobrietyV, checkGenderV] as Array<
    (p: Person) => Validation<Errors, Person>
  >
  return traverse(validation)(checks, f => f(p)).map(() => price(p))
}

console.log('-- Act Three --')
const bob = mkPerson('Male', 59, ['Jeans'], 'Paralytic')
console.log(costToEnter3(ken)) // success(29.5)
console.log(costToEnter3(ruby)) // failure(["Men only"])
console.log(costToEnter3(bob)) // failure(["Too Old!", "Smarten Up!", "Sober Up!"])