@w.dental/date-mask/dist/index.umd.js

Lib for using as maks for date input

/*!
 * @w.dental/date-mask v0.0.2
 * (c) W-Dental
 * Released under the MIT License.
 */
(function (global, factory) {
  typeof exports === 'object' && typeof module !== 'undefined' ? module.exports = factory() :
  typeof define === 'function' && define.amd ? define(factory) :
  (global = global || self, global.dateMask = factory());
}(this, (function () { 'use strict';

  var LETTERS_REGEX = /[a-z]/gi;
  var ONLY_NUMBERS_REGEX = /\D/gi;

  function dateMask(num) {
    if (num === void 0) {
      num = '';
    }

    if (typeof num !== 'string' || LETTERS_REGEX.test(num)) {
      throw new Error('You must to pass a digits as string with pattern DD/MM/YYYY or MM/DD/YYYY');
    }

    var numString = num.replace(ONLY_NUMBERS_REGEX, '');
    if (numString.length === 3) return numString.replace(/(\d{2})/, '$1/');
    if (numString.length > 3 && numString.length < 5) return numString.replace(/(\d{2})(\d+)/, '$1/$2');
    if (numString.length >= 5 && numString.length <= 8) return numString.replace(/(\d{2})(\d{2})(\d+)/, '$1/$2/$3');else return numString.substring(0, 10);
  }

  return dateMask;

})));