Number prototype method to return a digit at a specified position or a slice between two specified positions

getDigitAt.js

        /**
         * [getDigitAt method for numbers that will return either the digit at a specified position or the section of the number between two positions]
         * @param  {[number]} position1 [either the position to search for or the starting position of the slice]
         * @param  {[number]} position2 [*optional*, if supplied, this creates a slice and acts as the end position]
         * @return {[number]} [either the digit at the specified position or the slice between the specified positions]
         */
        Number.prototype.getDigitAt = function (position1, position2) {
          //convert the number to a string to allow array-like access
          var num = this.valueOf().toString();

          //check to see if one or two arguments were supplied
          if (arguments.length > 1) {
            //ensure that the second argument is a valid number. if the first argument is not a number, the function will just default it to 0, but if the second argument is not a number, it will return NaN. to fix this, we choose to return the entire number.
            if (!isNaN(position2) && position2 !== '') {
              //if two arguments were supplied and the second is valid, get the selected section of num
              num = num.slice(position1, position2);           
            }

            //parse num back into a number in base 10 and return it.
          } else {
            //handle a decimal value by truncating the decimal with the bitwise operator |. this is only an issue with one argument, because when two arguments are supplied, the function just rounds them off in slice();
            var _position = position1 | 0;
            //if only one argument is supplied, simply return the digit at that position
            return parseInt(num[_position], 10); 
          }
        }