CODE EXAMPLE FOR JAVASCRIPT

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;
}