Zahlensystem Converter JavaScript

Code.js

function convert(input, sourceUnit, targetUnit) {
    let result = "";
    let num = input;
    let temp = "";
    while (num > 0) {
        let remainder = num % sourceUnit;
        temp = remainder.toString(sourceUnit) + temp;
        num = Math.floor(num / sourceUnit);
    }
    let decimal = 0;
    let power = 0;
    for (let i = temp.length - 1; i >= 0; i--) {
        let char = temp.charAt(i);
        let digit = char.charCodeAt(0) <= 57 ? char - '0' : char.toUpperCase().charCodeAt(0) - 55;
        decimal += digit * Math.pow(sourceUnit, power);
        power++;
    }
    while (decimal > 0) {
        let remainder = decimal % targetUnit;
        result = (remainder > 9 ? String.fromCharCode(remainder + 55) : remainder) + result;
        decimal = Math.floor(decimal / targetUnit);
    }
    return result;
}