main.js

//начали писать свой блокчейн
const SHA256 = require('crypto-js/sha256');

class Block{
    constructor(index, timestamp, data, previousHash = ''){
        this.index = index;
        this.timestamp = timestamp;
        this.data = data;
        this.previousHash = previousHash;
        this.hash = this.calculateHash();
    }

    calculateHash() {
        return SHA256(this.index + this.previousHash + this.timestamp + JSON.stringify(this.data)).toString();
    }
}

class Blockchain {
    constructor() {
        this.chain[this.createGenesisBlock()];
    }

    createGenesisBlock(){
        return new Block(0, "01/01/2017", "Genesis block", "0");
    }

    getLatestBlock(){
        return this.chain[this.chain.length - 1];
    }
    addBlock(newBlock){
        newBlock.previousHash = this.getLatestBlock().hash;
        newBlock.hash = newBlock.calculateHash();
        this.chain.push(newBlock);
    }
}

let boboCoin = new Blockchain();
boboCoin.addBlock(new Block(1, "10/07/2017", { amount: 4 }));
boboCoin.addBlock(new Block(2, "12/07/2017", { amount: 10 }));

console.log(JSON.stringify(boboCoin, null, 4));