@getdelta/wallet-address-validator/src/stellar_validator.js

Wallet address validator for Bitcoin and other Altcoins.

const baseX = require('base-x');
const crc = require('crc');
const cryptoUtils = require('./crypto/utils');

const ALPHABET = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ234567';

const base32 = baseX(ALPHABET);
const regexp = new RegExp('^[' + ALPHABET + ']{56}$');
const ed25519PublicKeyVersionByte = (6 << 3);

function swap16(number) {
    const lower = number & 0xFF;
    const upper = (number >> 8) & 0xFF;
    return (lower << 8) | upper;
}

module.exports = {
    isValidAddress: function (address) {
        if (regexp.test(address)) {
            return this.verifyChecksum(address);
        }

        return false;
    },

     verifyChecksum: function (address) {
        // based on https://github.com/stellar/js-stellar-base/blob/master/src/strkey.js
        const bytes = base32.decode(address);
        if (bytes[0] !== ed25519PublicKeyVersionByte) {
            return false;
        }

        const payload = bytes.slice(0, -2);
        const checksum = cryptoUtils.toHex(bytes.slice(-2));
        const computedChecksum = cryptoUtils.numberToHex(swap16(crc.crc16xmodem(payload)), 2);
        return computedChecksum === checksum;
    }
};