Caterpillar.ts

enum Year {
  noPadding = "y",
  twoDigits = "yy",
  fourDigits = "yyyy"
}

enum Quarter {
  number = "Q",
  zeroPaddedNumber = "QQ",
  qAndNumber = "QQQ",
  spelledOut = "QQQQ"
}

enum Month {
  number = "M",
  zeroPaddedNumber = "MM",
  shortName = "MMM",
  fullName = "MMMM",
  narrowName = "MMMMM"
}

enum Day {
  number = "d",
  zeroPaddedNumber = "dd",
  dayOfWeekInMonth = "F",
  shortDayOfWeek = "E",
  fullDayOfWeek = "EEEE",
  narrowDayOfWeek = "EEEEE"
}

enum Hour {
  twelveHour = "h",
  zeroPaddedTwelveHour = "hh",
  twentyFourHour = "H",
  zeroPaddedTwentyFourHour = "HH",
  AMorPM = "a"
}

enum Minute {
  number = "m",
  zeroPaddedNumber = "mm"
}

enum Second {
  number = "s",
  zeroPaddedNumber = "ss"
}

enum TimeZone {
  threeLetterName = "zzz",
  expandedName = "zzzz",
  RFC822 = "Z",
  ISO8601 = "ZZZZZ"
}

enum Separator {
  dash = "-",
  slash = "/",
  colon = ":",
  space = " "
}

class Caterpillar {
  dateFormat: string = ""

  constructor(dateFormat: string) {
      this.dateFormat = dateFormat
  }

  private static with(formats: string[]) {
      return new Caterpillar(formats.reduce((a, b) => a + b, ''))
  }

  public static year(style: Year): Caterpillar {
      return new Caterpillar(style)
  }

  public static quarter(style: Quarter): Caterpillar {
      return new Caterpillar(style)
  }

  public static month(style: Month): Caterpillar {
      return new Caterpillar(style)
  }

  public static day(style: Day): Caterpillar {
      return new Caterpillar(style)
  }

  public static hour(style: Hour): Caterpillar {
      return new Caterpillar(style)
  }

  public static minute(style: Minute): Caterpillar {
      return new Caterpillar(style)
  }

  public static second(style: Second): Caterpillar {
      return new Caterpillar(style)
  }

  public static timeZone(style: TimeZone) {
      return new Caterpillar(style)
  }

  public static separator(separator: Separator) {
      return new Caterpillar(separator)
  }

  public static string(string: string): Caterpillar {
      return new Caterpillar(`'${string}'`) 
  }

  public year(style: Year): Caterpillar {
      return Caterpillar.with([this.dateFormat, style])
  }

  public quarter(style: Quarter): Caterpillar {
      return Caterpillar.with([this.dateFormat, style])
  }

  public month(style: Month): Caterpillar {
      return Caterpillar.with([this.dateFormat, style])
  }

  public day(style: Day): Caterpillar {
      return Caterpillar.with([this.dateFormat, style])
  }

  public hour(style: Hour): Caterpillar {
      return Caterpillar.with([this.dateFormat, style])
  }

  public minute(style: Minute): Caterpillar {
      return Caterpillar.with([this.dateFormat, style])
  }

  public second(style: Second): Caterpillar {
      return Caterpillar.with([this.dateFormat, style])
  }

  public timeZone(style: TimeZone) {
      return Caterpillar.with([this.dateFormat, style])
  }

  public separator(separator: Separator) {
      return Caterpillar.with([this.dateFormat, separator])
  }

  public string(string: string): Caterpillar {
      return Caterpillar.with([this.dateFormat, `'${string}'`]) 
  }
}