Check the balance of your Bitcoin HD wallet at the specified block height.

claim_checker.js

/**
 * @file claim_checker.js
 * 
 * Check the balance of your Bitcoin HD wallet at the specified block height.
 * This is usefull for checking what address is capable of receiving Stellar giveaway coins.
 */

const BASE_BLOCK_HEIGHT = 472889;
const HD_GAP_LIMIT = 20;

var async = require('async');
var request = require('request');
var bitcoin = require('bitcoinjs-lib');

if(process.argv.length < 3) {
	console.log('usage: node claim_checker.js xpub...');
	process.exit(1);
}

var check = function(xpub, callback) {
	var idx = 0;
	var nEmpty = 0;
	async.whilst(function() {
		return nEmpty < 20;
	}, function(cb) {
		var address = xpub.derive(idx).getAddress();
		request.get('https://api.blockcypher.com/v1/btc/main/addrs/' + address, function(err, res) {
			if(err) {
				console.log('E: failed to fetch data from blockexplorer: ' + err);
				process.exit(1);
			}
			var json = JSON.parse(res.body);
			if(!json.txrefs) {
				nEmpty++;
			} else {
				nEmpty = 0;
				var balance = 0;
				json.txrefs.forEach(function(tx) {
					if(tx.block_height > BASE_BLOCK_HEIGHT) return;
					balance += (tx.tx_input_n < 0 ? +1 : -1) * tx.value;
				});
				if(balance > 0) {
					console.log(address + '\t' + (balance*1e-8).toFixed(8) + 'BTC');
				}
			}
			idx++;
			cb();
		});
	}, function() {
		if(typeof callback == 'function') {
			callback();
		}
	});
};

var xpubStr = process.argv[2];
var xpub = bitcoin.HDNode.fromBase58(xpubStr);
async.series([
	function(cb) {
		check(xpub.derive(0), cb);
	},
	function(cb) {
		check(xpub.derive(1), cb);
	},
]);