Dan-Nolan

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

// buyer - puts the funds in the account
// arbiter - ability to move the funds
// recipient - receiver of the funds

// ERC20s common standard for tokens
interface IWethGateway {

Dan-Nolan

// https://goerli.etherscan.io/address/0xa423c1448d195d9cf2e06d343e30b35f501159ed
contract First {
    event Winner(address);

    function test() external {
        emit Winner(msg.sender);
    }
}

// https://goerli.etherscan.io/address/0x9a9a776bc00eb386fb56bb3a57e6b78595d93bf3

Dan-Nolan

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.13;

contract HelloWorld {
    bool public success;

    function doTheMath(uint _x, uint _y) external {
        require(_x + _y == 42); 
        require(_x > 0 && _y > 0); 
        success = true;

Dan-Nolan

const EC = require('elliptic').ec;

const ec = new EC('secp256k1');

// private/public key pair generation
const key = ec.genKeyPair();

// to public key hex string (04...)
const hexPublicKey = key.getPublic().encode('hex');
// from hex string back to the elliptic key object (this key can verify)

Dan-Nolan

// For learning purposes only! 
// Don't pollute the Array prototype in an application

// map synonym
Array.prototype.transform = function(callback) {
  const newArr = [];
  for(let i = 0; i < this.length; i++) {
    newArr.push(callback(this[i]));
  }
  return newArr;

Dan-Nolan

class MerkleTree {
    constructor(leaves, concat) {
        this.leaves = leaves;
        this.concat = concat;
    }
    getProof(index, leaves = this.leaves, proof = []) {
        if (leaves.length === 1) {
            return proof;
        }
        let newLayer = [];

Dan-Nolan

const SHA256 = require('crypto-js/sha256');
const TARGET_DIFFICULTY = BigInt(0x0fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff);
const MAX_TRANSACTIONS = 10;
const mempool = [];
const blocks = [];

function addTransaction(transaction) {
    mempool.push(transaction);
}

Dan-Nolan

const ethers = require('ethers');
const provider = ethers.getDefaultProvider('kovan');

const CONTACT_ADDR = "0xae4b4bda19d53178ebbad7737ba34beaa0107c18";
const ABI = [
	{
		"constant": true,
		"inputs": [],
		"name": "activeLength",
		"outputs": [

Dan-Nolan

{
  "difficulty": "0x153886c1bbd",
  "extraData": "0x657468706f6f6c2e6f7267",
  "gasLimit": "0x520b",
  "gasUsed": "0x5208",
  "hash": "0x4e3a3754410177e6937ef1f84bba68ea139e8d1a2258c5f85db9f1cd715a1bdd",
  "logsBloom": "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
  "miner": "0xe6a7a1d47ff21b6321162aea7c6cb457d5476bca",
  "mixHash": "0xb48c515a9dde8d346c3337ea520aa995a4738bb595495506125449c1149d6cf4",
  "nonce": "0xba4f8ecd18aab215",

Dan-Nolan

function verifyProof(proof, node, root, concat) {
    for(let i = 0; i < proof.length; i++) {
        let { left, data } = proof[i];
        if(left) {
            node = concat(data, node);
        }
        else {
            node = concat(node, data);
        }
    }