Quick command-line script to predict the next contract address for an account based off its current nonce and address.

nextContractAddr.js

var web3 = require('web3');
var rlp = require('rlp');
var process = require( 'process' );

var nonce = parseInt(process.argv[3]);
var account = process.argv[2];

var d = web3.utils.sha3(rlp.encode([account, nonce]));
console.log("0x"+d.substring(d.length-40));