main.js

const { SHA256 } = require("crypto-js");




class Block {
    constructor(index, timstamp, data, previousHash) {
        this.index = index;
        this.timstamp = timstamp;
        this.data = data;
        this.previousHash = previousHash;
        this.nonce = 0;
        this.hash = this.calculateHash();
    }
    calculateHash() {
        return SHA256(
            this.index +
                this.timstamp +
                this.previousHash +
                this.nonce +
                JSON.stringify(this.data),
        ).toString();
    }
    mineBlock(difficulty) {
        while (
            this.hash.substring(0, difficulty) !=
            Array(difficulty + 1).join("0")
        ) {
            this.nonce++;
            this.hash = this.calculateHash();
        }
        console.log("Block Minned " + this.hash);
    }
}

class BlockChain {
    constructor() {
        this.chain = [this.genisisBlock()];
        this.difficulty = Math.floor(Math.random() * 4) + 1;
    }
    genisisBlock() {
        return new Block(0, Date.now(), "Genisis Block", "0");
    }
    getLatestBlock() {
        return this.chain[this.chain.length - 1];
    }
    addNewBlock(newBlock) {
        newBlock.previousHash = this.getLatestBlock().hash;
        newBlock.mineBlock(this.difficulty);
        this.chain.push(newBlock);
    }
    isValidBlock() {
        for (let i = 0; i < this.chain.length; i++) {
            const currentBlock = this.chain[i];
            const previousBlock = this.chain[i - 1];

            if (currentBlock.hash != currentBlock.calculateHash()) {
                return false;
            }
            if (previousBlock.hash != currentBlock.previousHash) {
                return false;
            }
        }
        return true;
    }
}

let GodCoin = new BlockChain();
console.log("Creating block 1...");
GodCoin.addNewBlock(new Block(1, Date.now(), "4 paise"));
console.log("Creating block 2...");
GodCoin.addNewBlock(new Block(2, Date.now(), "5 paise"));
console.log("Creating block 3...");
GodCoin.addNewBlock(new Block(2, Date.now(), "6 paise"));