Tusidan number converter (digits)

tusidan_numbers.js

//Why does this exist
/*Floating point warning: This is subject to the limitations of the IEEE 754
double-precision binary floating-point type JavaScript uses. This can lead
to precision loss. If you are converting big numbers with lots of decimals
(like the number 1,000,000,000,000.39930209809), this loss can be severe.*/

//from https://stackoverflow.com/questions/6259515/how-can-i-split-a-string-into-segments-of-n-characters
//modified and more modified
function splitString(str,chars) {
    var chunks = [];
    for (var i = 0, charsLength = str.length; i < charsLength; i += chars) {
        chunks.push(str.substring(i, i + chars));
    };
    return chunks;
};

function splitStringFromEnd(str,chars) {
    var chunks = [];
    for (var i = str.length, charsLength = 0; i > -1; i -= chars) {
        chunks.unshift(str.substring(i - chars, i));
    };
    return chunks.filter(function(str) { return str !== '' });
};

function numberToTusidan(number,doSeparators=true) {
    if(!(["bigint","number"].includes(typeof(number)))) {
        throw new TypeError("Input must be a number or bigint");
    };
    
    var numberBase12 = number.toString(12);
    var result = "";

    digits = "0123456789ab.";
    var tusidanDigits = "८r^ⵠп□ⅎㅂ⧄≡7૯`";
    
    for(i = 0; i < numberBase12.length; i++) {
    　　 ind = digits.indexOf(numberBase12.charAt(i));
    　　 result += tusidanDigits[ind] ?? numberBase12.charAt(i);
    };

    if(doSeparators) {
        result = result.split("`");
        result[0] = splitStringFromEnd(result[0],4).join(".");
        if(result[1]) {
            result[1] = splitString(result[1],4).join(".");
        };
        result = result.join("`");
    };
    
    return result;
};

//https://stackoverflow.com/questions/8555649/second-argument-to-parsefloat-in-javascript
function parseFloatWithRadix(s, r) {
  r = (r||10)|0;
  const [b,a] = ((s||'0') + '.').split('.');
  const l1 = parseInt('1'+(a||''), r).toString(r).length;
  return parseInt(b, r) + 
    parseInt(a||'0', r) / parseInt('1' + Array(l1).join('0'), r);
}

function numberFromTusidan(numberString) {
    var tusidanAlphabet = ["८", "r", "^", "ⵠ", "п", "□", "ⅎ", "ㅂ", "⧄", "≡", "7", "૯", "`", "."];
    haBaseTwelveDigits = ["0","1","2","3","4","5","6","7","8","9","a","b",".",""];
    
    var result = "";

    for(i = 0; i < numberString.length; i++) {
    　　ind = tusidanAlphabet.indexOf(numberString.charAt(i));
    　　result += haBaseTwelveDigits[ind] ?? numberString.charAt(i);
    };

    var numberValue = parseFloatWithRadix(result,12);

    if(isNaN(numberValue)) {
        throw new Error(`NaN value from converting number ${numberString}`);
    };

    return numberValue;
};