Typescript - Typed date strings using template string literal.

date-types.ts

/**
 * @desc range 0 - 9
 */
type Digit = '0' | '1' | '2' | '3' | '4' | '5' | '6' | '7' | '8' | '9'

export declare namespace ISO8601 {
  /**
   * @desc range 00 - 24
   */
  type TimeHour = `${'0' | '1' | '2'}${'0' | '1' | '2' | '3' | '4'}`
  
  /**
   * @desc range 00 - 59
   */
  type TimeMinute = `${0 | 1 | 2 | 3 | 4 | 5}${Digit}`
  
  /**
   * @desc range 00 - 59
   */
  type TimeSecond = `${0 | 1 | 2 | 3 | 4 | 5}${Digit}`
  
  /**
   * @desc range  00 - 29
   */
  type DateCentury = `${'0' | '1' | '2'}${Digit}`
  
  /**
   * @desc range 0 - 9
   */
  type DateDecade = `${Digit}`
  
  /**
   * @desc range 0-9
   */
  type DateSubDecade = `${Digit}`
  
  /**
   * @desc range 00 - 99
   */
  type DateYear = `${DateDecade}${DateSubDecade}`
  
  /**
   * @desc range 0000 - 2999
   */
  type DateYearFull = `${DateCentury}${DateYear}`
  
  /**
   * @desc range from 01 - 12
   */
  type DateMonth = `${'01' | '02' | '03' | '04' | '05' | '06' | '07' | '08' | '09' | '10' | '11' | '12'}`
  
  /**
   * @desc range  0000-01 - 2999-12
   */
  type DateYearAndMonth = `${DateYearFull}-${DateMonth}`
}

// Example
const date: ISO8601.DateYearAndMonth = '1980-02'

A Simple version (without full editor support) would be:

type Date = `${number}-${number}-${number}T${number}:${number}:${number}Z`