node-blockchain-js/lib/CryptoBlockchain.js

Simple implementation of Crypto Blockchain using Node.js

const CryptoBlock = require("./CryptoBlock");

class CryptoBlockchain{
    constructor(){
        this.blockchain = [];
    }
    initBlock(){
        return new CryptoBlock("Initial Block in the Chain");
    }
    getLatestBlock(){
        return this.blockchain[this.blockchain.length - 1];
    }
    addNewBlock(newBlock){

        newBlock.index = this.blockchain.length;
        
        if(newBlock.index > 0)
            newBlock.previousHash = this.getLatestBlock().hash;
        
        newBlock.computeHash();    

        if(this.checkValidity) 
            this.blockchain.push(newBlock);
        else 
            throw "Blockchain not valid";
    }
    checkValidity(){
        for(let i = 1; i < this.blockchain.length; i++){
            const currentBlock = this.blockchain[i];
            const previousBlock= this.blockchain[i-1];

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

module.exports = {
    CryptoBlockchain: CryptoBlockchain,
    CryptoBlock: CryptoBlock
}