Adding Proof of Work to blockchain
Blockchain.prototype.proofOfWork = function(prevBlockHash, currentBlockData) { let nonce = 0; let hash = this.hashBlock(prevBlockHash, currentBlockData, nonce); while (hash.substring(0,4) !== '0000') { nonce++; hash = this.hashBlock(prevBlockHash, currentBlockData, nonce); } return nonce; }
Source: softhunt.net