block.js

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;
    // When creating a new Block, automatically calculate its hash.
    this.hash = this.calculateHash();
    this.nonce = 0;
  }

  calculateHash() {
    return SHA256(this.index + this.previousHash + this.timestamp + JSON.stringify(this.data) + this.nonce).toString();
  }
  
  mineBlock(difficulty) {
    while (this.hash.substring(0, difficulty) !== Array(difficulty + 1).join("0")) {
      this.nonce++;
      this.hash = this.calculateHash();
    }
    console.log("BLOCK MINED: " + this.hash);
  }
}

module.exports = Block;