index.js

/**
 * MIT License
 * Copyright (c) 2020 Naveen Bharathi
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
*/

/**
 * Get ordinal numbers like 1-st, 2-nd, 3-rd.
 *
 * @param {Number} number  Number for which the ordinal is needed.
 * @return {String}  Ordinal string.
 */
const getOrdinalNumber = (number) => {
  if (!Number.isInteger(number)) { throw new TypeError('The passed parameter is not an integer.'); }
  const ordinals = {
    1: 'st', 2: 'nd', 3: 'rd', 4: 'th', 5: 'th', 6: 'th', 7: 'th', 8: 'th', 9: 'th', 0: 'th',
  };
  return (!(number.toString().length > 1 && Math.floor((number % 100) / 10) === 1)) ? ordinals[number % 10] : 'th';
};

module.exports = getOrdinalNumber;