bech32.js

var ALPHABET = 'qpzry9x8gf2tvdw0s3jn54khce6mua7l';
var ALPHABET_MAP = {};
for (var z = 0; z < ALPHABET.length; z++) {
    var x = ALPHABET.charAt(z);
    ALPHABET_MAP[x] = z;
}
function polymodStep(pre) {
    var b = pre >> 25;
    return (((pre & 0x1ffffff) << 5) ^
        (-((b >> 0) & 1) & 0x3b6a57b2) ^
        (-((b >> 1) & 1) & 0x26508e6d) ^
        (-((b >> 2) & 1) & 0x1ea119fa) ^
        (-((b >> 3) & 1) & 0x3d4233dd) ^
        (-((b >> 4) & 1) & 0x2a1462b3));
}
function prefixChk(prefix) {
    var chk = 1;
    for (var i = 0; i < prefix.length; ++i) {
        var c = prefix.charCodeAt(i);
        if (c < 33 || c > 126)
            return 'Invalid prefix (' + prefix + ')';
        chk = polymodStep(chk) ^ (c >> 5);
    }
    chk = polymodStep(chk);
    for (var i = 0; i < prefix.length; ++i) {
        var v = prefix.charCodeAt(i);
        chk = polymodStep(chk) ^ (v & 0x1f);
    }
    return chk;
}
function convertbits(data, inBits, outBits, pad) {
    var value = 0;
    var bits = 0;
    var maxV = (1 << outBits) - 1;
    var result = [];
    for (var i = 0; i < data.length; ++i) {
        value = (value << inBits) | data[i];
        bits += inBits;
        while (bits >= outBits) {
            bits -= outBits;
            result.push((value >> bits) & maxV);
        }
    }
    if (pad) {
        if (bits > 0) {
            result.push((value << (outBits - bits)) & maxV);
        }
    }
    else {
        if (bits >= inBits)
            return 'Excess padding';
        if ((value << (outBits - bits)) & maxV)
            return 'Non-zero padding';
    }
    return result;
}
function toWords(bytes) {
    return convertbits(bytes, 8, 5, true);
}
function fromWordsUnsafe(words) {
    var res = convertbits(words, 5, 8, false);
    if (Array.isArray(res))
        return res;
}
function fromWords(words) {
    var res = convertbits(words, 5, 8, false);
    if (Array.isArray(res))
        return res;
    throw new Error(res);
}
function getLibraryFromEncoding(encoding) {
    var ENCODING_CONST;
    if (encoding === 'bech32') {
        ENCODING_CONST = 1;
    }
    else {
        ENCODING_CONST = 0x2bc830a3;
    }
    function encode(prefix, words, LIMIT) {
        LIMIT = LIMIT || 90;
        if (prefix.length + 7 + words.length > LIMIT)
            throw new TypeError('Exceeds length limit');
        prefix = prefix.toLowerCase();
        // determine chk mod
        var chk = prefixChk(prefix);
        if (typeof chk === 'string')
            throw new Error(chk);
        var result = prefix + '1';
        for (var i = 0; i < words.length; ++i) {
            var x = words[i];
            if (x >> 5 !== 0)
                throw new Error('Non 5-bit word');
            chk = polymodStep(chk) ^ x;
            result += ALPHABET.charAt(x);
        }
        for (var i = 0; i < 6; ++i) {
            chk = polymodStep(chk);
        }
        chk ^= ENCODING_CONST;
        for (var i = 0; i < 6; ++i) {
            var v = (chk >> ((5 - i) * 5)) & 0x1f;
            result += ALPHABET.charAt(v);
        }
        return result;
    }
    function __decode(str, LIMIT) {
        LIMIT = LIMIT || 90;
        if (str.length < 8)
            return str + ' too short';
        if (str.length > LIMIT)
            return 'Exceeds length limit';
        // don't allow mixed case
        var lowered = str.toLowerCase();
        var uppered = str.toUpperCase();
        if (str !== lowered && str !== uppered)
            return 'Mixed-case string ' + str;
        str = lowered;
        var split = str.lastIndexOf('1');
        if (split === -1)
            return 'No separator character for ' + str;
        if (split === 0)
            return 'Missing prefix for ' + str;
        var prefix = str.slice(0, split);
        var wordChars = str.slice(split + 1);
        if (wordChars.length < 6)
            return 'Data too short';
        var chk = prefixChk(prefix);
        if (typeof chk === 'string')
            return chk;
        var words = [];
        for (var i = 0; i < wordChars.length; ++i) {
            var c = wordChars.charAt(i);
            var v = ALPHABET_MAP[c];
            if (v === undefined)
                return 'Unknown character ' + c;
            chk = polymodStep(chk) ^ v;
            // not in the checksum?
            if (i + 6 >= wordChars.length)
                continue;
            words.push(v);
        }
        if (chk !== ENCODING_CONST)
            return 'Invalid checksum for ' + str;
        return { prefix: prefix, words: words };
    }
    function decodeUnsafe(str, LIMIT) {
        var res = __decode(str, LIMIT);
        if (typeof res === 'object')
            return res;
    }
    function decode(str, LIMIT) {
        var res = __decode(str, LIMIT);
        if (typeof res === 'object')
            return res;
        throw new Error(res);
    }
    return {
        decodeUnsafe: decodeUnsafe,
        decode: decode,
        encode: encode,
        toWords: toWords,
        fromWordsUnsafe: fromWordsUnsafe,
        fromWords: fromWords
    };
}

const bech32 = getLibraryFromEncoding('bech32');
const bech32m = getLibraryFromEncoding('bech32m');