text: const { NotImplementedError } = require('../extensions/index.js');
  
  const MODERN_ACTIVITY = 15;
  const HALF_LIFE_PERIOD = 5730;
  
  /**
   * Determine the age of archeological find by using
   * given MODERN_ACTIVITY and HALF_LIFE_PERIOD values
   * 
   * @param {String} sampleActivity string representation of current activity 
   * @return {Number | Boolean} calculated age in years or false
   * in case of incorrect sampleActivity
   *
   * @example
   * 
   * dateSample('1') => 22387
   * dateSample('WOOT!') => false
   *
   */
  function dateSample(sampleActivity) {  
    if (typeof(sampleActivity) !== 'string' || sampleActivity.length === 0 || sampleActivity === " " || isNaN(sampleActivity) || Number(sampleActivity) > 15 || Number(sampleActivity) <= 0) return false;
    return Math.ceil(Math.log(MODERN_ACTIVITY / Number(sampleActivity)) / (0.693 / HALF_LIFE_PERIOD));
  }
  
  module.exports = {
    dateSample
  };
  