Base56 random character generation.

base56.js

// Thanks to https://github.com/evanx/secret-base56

const letters24 = 'ABCDEFGHJKLMNPQRSTUVWXYZ'; // exclude I and O since too similar to 0 and 1
const digits8 = '23456789'; // omit 0 and 1 to avoid potential confusion with O and I (and perhaps 'l')
const charset = [digits8, letters24, letters24.toLowerCase()].join('');

module.exports = length => Array(length)
                                .fill()
                                .map(() => charset[Math.floor(Math.random() * 56)])
                                .join('');

Usage:

const base56 = require('./base56');

console.log(`Public Address: 3${base56(33)}`); // Random Bitcoin address