64id - an id encoding for more readable urls, but still keeping a long number

64id.js

function EncodeDigit(digit) {

    if (digit < 10)
        return digit + 48

    else if (digit < 36)
        return digit + 97 - 10

    else if (digit < 62)
        return digit + 65 - 36

    else if (digit == 62)
        return "_"

    else if (digit == 63)
        return "$"
}

function EncodeNumber(number) {

    let digit = EncodeDigit(number % 64);
    // console.log(`char[${number % 64}] = ${digit} => ${String.fromCodePoint(digit)}`)

    let x = (number >= 64 ? EncodeNumber(Math.floor(number / 64)) : "") + String.fromCodePoint(digit);

    return x;
}

function DecodeDigit(char) {

    let digit = char.charCodeAt(0);

    if (digit == 95)
        return 62

    if (digit == 36)
        return 63

    if (digit >= 97)
        return digit - 87

    if (digit >= 65)
        return digit - 29

    if (digit >= 48)
        return digit - 48
}

function DecodeNumber(number) {

    return [...number].reduceRight((acc, x, i) => {

        let digit = DecodeDigit(x)
        let index = Math.pow(64, number.length - i - 1)
        let value = index * digit

        // console.log(`[${x}] = ${digit} * 64^${index} = ${value} | acc: ${acc}`)

        return acc + value
    }, 0)
}

let encoded = EncodeNumber(123454321)
console.log(encoded);
console.log(DecodeNumber(encoded));