messages.test.ts

/* eslint-disable prettier/prettier */
// type Input = { code : ErrorMessageKind } | { code: 'illegalWeekday', weekday?: string }
// code: 'illegalEmailDomain', email: string, allowedDomains: string[]

type ErrorMessageKind = "networkError" | "generalError" | 'illegalWeekday'

interface Message {
  NO: string
  EN: string
}

class GeneralError implements Message {
  NO = 'En feil har intruffet'
  EN = 'An error has ocurred'
}

class NetworkError implements Message {
  NO = 'En nettverksfeil har inntruffet'
  EN = 'A Network error has occured'
}

class IllegalWeekday implements Message {
  EN = 'Illegal weekday'
  NO = 'Ulovlig ukedag'

  constructor(day?: string) {
    if (!day) return
    
    this.EN = `'${day}' er ulovlig`
    this.NO = `'${day}' is illegal`
  }
}

type Input = { code: ErrorMessageKind, weekday?: string }

describe("messages", () => {
  it("translates a message in english", () => {
    expect(translateMessage({ code: "generalError" }, "EN")).toBe("An error has ocurred");
  });

  it("translates a message in norwegain", () => {
    expect(translateMessage({ code: "generalError" }, "NO")).toBe(
      "En feil har intruffet"
    );
  });

  it("Expext a network error", () => {
    expect(translateMessage({ code: "networkError" }, "NO")).toBe("En nettverksfeil har inntruffet")
  })

  it("Shows a message with argument", () => {
    expect(translateMessage({ code: "illegalWeekday", weekday: 'Doomsday' }, "NO")).toBe("'Doomsday' is illegal")
  })

  it("Shows a message with argument", () => {
    expect(translateMessage({ code: "illegalWeekday", weekday: 'Payday' }, "NO")).toBe("'Payday' is illegal")
  })

  // it("Shows a message with more array arguments", () => {
  //   expect(translateMessage({ code: "illegalEmailDomain", email: 'Payday' }, "NO")).toBe("'Payday' is illegal")
  // })
});

function translateMessage(kind: Input, locale: "EN" | 'NO') {

  const ErrorKind = ({
    "networkError": NetworkError,
    "generalError": GeneralError,
    "illegalWeekday": IllegalWeekday
  })[kind.code]

  
  return new ErrorKind(kind.weekday)[locale]
}

WIP from a workshop regarding testing for error handling. Had an idea w/ classes that turned out kinda nice, so keeping it here for reference