@mark01/express-utils/lib/core/util/base32.js

npm package that contains utilities for express.js

export const b32ToBuf = (str) => {
    str = str.toUpperCase().replace(/=+$/, '');
    const alphabet = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ234567';
    const buf = new ArrayBuffer(((str.length * 5) / 8) | 0);
    const arr = new Uint8Array(buf);
    let bits = 0;
    let value = 0;
    let index = 0;
    for (let i = 0; i < str.length; i++) {
        const idx = alphabet.indexOf(str[i]);
        if (idx === -1)
            throw new TypeError(`b32ToBuf: Invalid character found: ${str[i]}.`);
        value = (value << 5) | idx;
        bits += 5;
        if (bits >= 8) {
            arr[index++] = (value >>> (bits - 8)) & 255;
            bits -= 8;
        }
    }
    return buf;
};
export const b32FromBuf = (buf) => {
    const alphabet = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ234567';
    const arr = new Uint8Array(buf);
    let bits = 0;
    let value = 0;
    let str = '';
    for (let i = 0; i < arr.length; i++) {
        value = (value << 8) | arr[i];
        bits += 8;
        while (bits >= 5) {
            str += alphabet[(value >>> (bits - 5)) & 31];
            bits -= 5;
        }
    }
    if (bits > 0) {
        str += alphabet[(value << (5 - bits)) & 31];
    }
    while (str.length % 8 !== 0) {
        str += '=';
    }
    return str;
};