verifyBlock.js

function verifyBlock(data){

	const block = JSON.parse(data);

	signer = block.signer;
	signature = block.signature;
	
	v =  cat.GeneratorUtils.uintToBuffer(block.version, 1) //version:8
	n =  cat.GeneratorUtils.uintToBuffer(block.networkType, 1) //network:8
	t =  cat.GeneratorUtils.uintToBuffer(block.type, 2) //type:16
	h =  cat.GeneratorUtils.uint64ToBuffer([block.height.lower,block.height.higher]) //height
	ts = cat.GeneratorUtils.uint64ToBuffer([block.timestamp.lower,block.timestamp.higher]) //timestamp
	df = cat.GeneratorUtils.uint64ToBuffer([block.difficulty.lower,block.difficulty.higher]) //difficulty
	ph = nem.Convert.hexToUint8(block.previousBlockHash) //prehash
	th = nem.Convert.hexToUint8(block.blockTransactionsHash) //txhash
	rh = nem.Convert.hexToUint8(block.blockReceiptsHash) //rcpthash
	sh = nem.Convert.hexToUint8(block.stateHash) //stathash
	bp = nem.Convert.hexToUint8(block.beneficiaryPublicKey.publicKey) //benepubkey
	fm = cat.GeneratorUtils.uintToBuffer(block.feeMultiplier, 4) // feeMultiplier:32

	const buffer = Array.from(v)
	  .concat(Array.from(n))
	  .concat(Array.from(t))
	  .concat(Array.from(h))
	  .concat(Array.from(ts))
	  .concat(Array.from(df))
	  .concat(Array.from(ph))
	  .concat(Array.from(th))
	  .concat(Array.from(rh))
	  .concat(Array.from(sh))
	  .concat(Array.from(bp))
	  .concat(Array.from(fm));

	const hex = nem.Convert.uint8ToHex(buffer);

	var hasher = jssha3.sha3_256.create();
	hasher.update(nem.Convert.hexToUint8(signature)); //signature
	hasher.update(nem.Convert.hexToUint8(signer.publicKey)); //publicKey
	const hash = hasher.update(buffer).hex().toUpperCase();
	console.log("calc  hash:" + hash);
	console.log("block hash:" + block.hash);
}