JavaScript-BlockChain/main.js at master · bmo91/JavaScript-BlockChain · GitHub

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constSHA256=require('crypto-js');

classtransactions{
constructor(fromAddress,toAdress,amount){
this.fromAddress=fromAddress;
this.toAdress=toAdress;
this.amount=amount;
}
}

classBlock{
constructor(timestamp,transactions,previousHash=''){

this.timestamp=timestamp;
this.transactions=transactions;
this.previousHash=previousHash;
this.hash=this.calculateHash();
this.nonce=0;
}

calculateHash(){
returnSHA256(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-this.calculateHash();
}

console.log("Block mined: "+this.hash);
}
}


classBlockchain{
constructor(){
this.chain=[this.createGenesisBlock()];
this.difficulty=2;
this.pendingTransactions=[];
this.miningReward=100;
}

createGenesisBlock(){
returnnewBlock("01/01/2017","Genesis block","0");
}

getLatestBlock(){
returnthis.chain[this.chain.length-1];
}

/*addBlock(newBlock){
 newBlock.previousHash = this.getLatestBlock().hash;
 newBlock.mineBlock(this.difficulty);
 this.chain.push(newBlock);
 }*/

minePendingTransactions(miningRewardAddress){
letblock=newBlock(Data.now(),this.pendingTransactions);
block.mineBlock(this.difficulty);

console.log("Block successfully mined");
this.chain.push(block);

this.pendingTransactions=[
newTransactions(null,miningRewardAddress,this.miningReward)
];
}

createTransaction(transactions){
this.pendingTransactions.push(transactions);
}

getBalanceOfAddress(address){
letbalance=0;

for(constblockofthis.chain){
for(consttransofblock.transactions){
if(trans.fromAddress===address){
balance-=trans.amount;
}
}
}

returnbalance;
}

isChainValid(){
for(leti=1;i<this.chain.length;i++){
constcurrentBlock=this.chain[i];
constpreviousBlock=this.chain[i-1];

if(currentBlock.hash!=currentBlock.calculateHash()){
returnfalse;
}

if(currentBlock.previousHash!=previousBlock.hash){
returnfalse;
}
}

returntrue;
}
}

letbmoCoin=newBlockchain();
bmoCoin.createTransaction(newTransactions("address1, address 2",100));
bmoCoin.createTransaction(newTransactions("address2, address 1",50));

console.log("\n Starting the miner...");
bmoCoin.minePendingTransactions('bmo-address');

console.log("\nBalance of BMO is",bmoCoin.getBalanceOfAddress('bmo-address'));

console.log("\n Starting the miner again...");
bmoCoin.minePendingTransactions('bmo-address');

console.log("\nBalance of BMO is",bmoCoin.getBalanceOfAddress('bmo-address'));

/*console.log("Mining block 1...");
bmoCoin.addBlock(new Block(1, "10/07/2017", {amount: 4}));

console.log("Mining block 2...");
bmoCoin.addBlock(new Block(2, "12/07/2017", {amount: 10}));*/