Method isSafeInteger

src/Encoder/NumeralSystem.js:206–212

* Determines whether the provided value is a `Number` that is a safe integer. * @param {Number} testValue * @return {Boolean}

(testValue)

   * @return {Boolean}
   */
  static isSafeInteger (testValue) {
    if (Number.isSafeInteger === undefined) {
      const maxInteger = Number.MAX_SAFE_INTEGER || 9007199254740991
      return Number.isInteger(testValue) && Math.abs(testValue) <= maxInteger
    }
    return Number.isSafeInteger(testValue)
  }

  /**
   * Translates given decimal to roman numerals.