require("crypto-js")
// create a SHA256 constant and pull the information directly
const SHA256 = require('crypto-js/sha256')
class Block {
constructor(timestamp, data) {
this.index = 0;
this.timestamp = timestamp;
this.data = data;
this.previousHash = "0";
this.hash = this.calculateHash();
this.nonce = 0;
}
calculateHash() {
return SHA256(this.index + this.previousHash + this.timestamp + this.data + this.nonce).toString();
}
mineBlock(difficulty) {
}
}
class Blockchain{
constructor() {
this.chain = [this.createGenesis()];
}
createGenesis() {
return new Block(0, "01/01/2018", "Genesis block", "0")
}
latestBlock() {
return this.chain[this.chain.length - 1]
}
addBlock(newBlock){
newBlock.previousHash = this.latestBlock().hash;
newBlock.hash = newBlock.calculateHash();
this.chain.push(newBlock);
}
checkValid() {
for(let i = 1; i < this.chain.length; i++) {
const currentBlock = this.chain[i];
const previousBlock = this.chain[i - 1];
if (currentBlock.hash !== currentBlock.calculateHash()) {
return false;
}
if (currentBlock.previousHash !== previousBlock.hash) {
return false;
}
}
return true;
}
}
let jsChain = new Blockchain();
jsChain.addBlock(new Block("05/25/2018", {amount: 5}));
jsChain.addBlock(new Block("05/26/2018", {amount: 10}));
console.log(JSON.stringify(jsChain, null, 4));
console.log("Is blockchain valid? " + jsChain.checkValid());
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