Gist for my medium article on blockchain

pow.js

  validProof (lastProof, proof) {
    const guessHash = crypto.createHmac(process.env.HASH_TYPE, process.env.CRYPTO_SECRET)
    .update(`${lastProof}${proof}`)
    .digest('hex')
    return guessHash.substr(0, 5) === process.env.RESOLUTION_HASH
  }

  proofOfWork (lastProof) {
    let proof = 0
    while (true) {
      if (!this.validProof(lastProof, proof)) {
        proof++
      } else {
        break
      }
    }
    return proof
  }