otp-io/dist/base32.mjs

🕖 Typed library to work 2fa via Google Authenticator/Time-based TOTP/Hmac-based HOTP

const charTable = "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567";
const byteTable = new Uint8Array([
    0xff, 0xff, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 0xff, 0xff, 0xff, 0xff, 0xff,
    0xff, 0xff, 0xff, 0xff, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08,
    0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15,
    0x16, 0x17, 0x18, 0x19, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00, 0x01, 0x02,
    0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
    0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0xff, 0xff, 0xff,
    0xff, 0xff
]);
/**
 *
 *
 * @param {Uint8Array} buffer
 * @return {number}
 */
function quintetCount(buffer) {
    return Math.ceil(buffer.length / 5);
}
/**
 *
 *
 * @export
 * @param {Uint8Array} plain
 * @return {string}  {string}
 */
function encode(plain, { pad = true } = {}) {
    let index = 0;
    let encodedIndex = 0;
    let shiftIndex = 0;
    let digit = 0;
    const encoded = Array.from({ length: quintetCount(plain) * 8 });
    while (index < plain.length) {
        const current = plain[+index];
        if (shiftIndex > 3) {
            digit = current & (0xff >> shiftIndex);
            shiftIndex = (shiftIndex + 5) % 8;
            digit =
                (digit << shiftIndex) |
                    ((index + 1 < plain.length ? plain[index + 1] : 0) >> (8 - shiftIndex));
            index++;
        }
        else {
            digit = (current >> (8 - (shiftIndex + 5))) & 0x1f;
            shiftIndex = (shiftIndex + 5) % 8;
            if (shiftIndex === 0)
                index++;
        }
        encoded[+encodedIndex] = charTable.codePointAt(digit);
        encodedIndex++;
    }
    if (pad) {
        for (index = encodedIndex; index < encoded.length; index++) {
            encoded[+index] = 0x3d;
        }
    }
    else {
        encoded.splice(encodedIndex);
    }
    return String.fromCharCode(...encoded);
}
/**
 *
 *
 * @export
 * @param {string} encoded
 * @return {Uint8Array}  {Uint8Array}
 */
function decode(encoded) {
    let shiftIndex = 0;
    let plainDigit = 0;
    let plainChar = 0;
    let plainPos = 0;
    const decoded = new Uint8Array(Math.ceil((encoded.length * 5) / 8));
    const chars = encoded.split("").map((char) => char.charCodeAt(0));
    for (let index = 0; index < encoded.length; index++) {
        if (chars[+index] === 0x3d) {
            break;
        }
        const encodedByte = chars[+index] - 0x30;
        if (encodedByte < byteTable.length) {
            plainDigit = byteTable[+encodedByte];
            if (shiftIndex <= 3) {
                shiftIndex = (shiftIndex + 5) % 8;
                if (shiftIndex === 0) {
                    plainChar |= plainDigit;
                    decoded[+plainPos] = plainChar;
                    plainPos++;
                    plainChar = 0;
                }
                else {
                    plainChar |= 0xff & (plainDigit << (8 - shiftIndex));
                }
            }
            else {
                shiftIndex = (shiftIndex + 5) % 8;
                plainChar |= 0xff & (plainDigit >>> shiftIndex);
                decoded[+plainPos] = plainChar;
                plainPos++;
                plainChar = 0xff & (plainDigit << (8 - shiftIndex));
            }
        }
        else {
            throw new Error("Invalid input - it is not base32 encoded string");
        }
    }
    return decoded.slice(0, plainPos);
}export{decode,encode};