base36converter.js

/*
  Converts any integer into a base [BASE] number. I have chosen 36
  as it is meant to represent the integers using case-insensitive alphanumeric
  characters, [no special characters] = {0..9}, {A..Za..z}
 
  I plan on using this to shorten the representation of possibly long ids,
  a la url shortenters

  base36.saturate('5t6C9')  takes the base 36 key, as a string, and turns it back into an integer
  base36.dehydrate(9759321) takes an integer and turns it into the base 36 string
*/
var base36 = {
    BASE: 36,
    LOWERCASEOFFSET: 87,
    DIGITOFFSET: 48,
    trueOrd: function(char) {
        var ord = char.toLowerCase().charCodeAt(0);
        if (ord >= 48 && ord <= 57) {
            return ord - this.DIGITOFFSET;
        } else if (ord >= 97 && ord <= 122) {
            return ord - this.LOWERCASEOFFSET;
        } else {
            throw new Error(char + " is not a valid character");
        }
    },
    trueChr: function(integer) {
        if (integer < 10) {
            return String.fromCharCode(integer + this.DIGITOFFSET);
        } else if (integer >= 10 && integer <= 35) {
            return String.fromCharCode(integer + this.LOWERCASEOFFSET);
        } else {
            throw new Error(integer + " is not a valid integer in the range of base " + this.BASE);
        }
    },
    saturate: function(key) {
        var intSum = 0,
            reversedKey = key.split('').reverse().join(''),
            char = '';
        for (var i = 0; i < reversedKey.length; i++) {
            char = reversedKey[i];
            intSum += this.trueOrd(char) * parseInt(Math.pow(this.BASE, i));
        }
        return intSum;
    },
    dehydrate: function(integer) {
        var str = '',
            remainder = 0;
        if (integer == 0) {
            return '0';
        }
        while (integer > 0) {
            remainder = integer % this.BASE;
            str = this.trueChr(remainder) + str;
            integer = Math.floor(integer / this.BASE);
        }
        return str;
    }
};