feat(TxBuilder): Add helper for producing tx hash

es/tx/builder/helpers.js

@@ -36,6 +36,18 @@ export function buildContractId (ownerId, nonce) {
   return encode(b2bHash, 'ct')
 }
 
+/**
+ * Build hash
+ * @function
+ * @alias module:@aeternity/aepp-sdk/es/tx/builder/helpers
+ * @param {String} prefix Transaction hash prefix
+ * @param {Buffer} data Rlp encoded transaction buffer
+ * @return {String} Transaction hash
+ */
+export function buildHash (prefix, data) {
+  return encode(hash(data), prefix)
+}
+
 /**
  * Build a oracle query id
  * @function
@@ -206,5 +218,6 @@ export default {
   commitmentHash,
   formatSalt,
   oracleQueryId,
-  createSalt
+  createSalt,
+  buildHash
 }

es/tx/builder/index.js

@@ -14,7 +14,7 @@ import {
   VALIDATION_MESSAGE,
   VSN
 } from './schema'
-import { readInt, readId, readPointers, writeId, writeInt, buildPointers, encode, decode } from './helpers'
+import { readInt, readId, readPointers, writeId, writeInt, buildPointers, encode, decode, buildHash } from './helpers'
 import { toBytes } from '../../utils/bytes'
 import * as mpt from '../../utils/mptree'
 
@@ -362,4 +362,16 @@ export function unpackTx (encodedTx, fromRlpBinary = false) {
   return { txType: OBJECT_ID_TX_TYPE[objId], tx: unpackRawTx(binary, schema), rlpEncoded, binary }
 }
 
-export default { calculateMinFee, calculateFee, unpackTx, unpackRawTx, buildTx, buildRawTx, validateParams }
+/**
+ * Build a transaction hash
+ * @function
+ * @alias module:@aeternity/aepp-sdk/es/tx/builder/helpers
+ * @param {String | Buffer} rawTx base64 or rlp encoded transaction
+ * @return {String} Transaction hash
+ */
+export function buildTxHash (rawTx) {
+  if (typeof rawTx === 'string' && rawTx.indexOf('tx_') !== -1) return buildHash('th', unpackTx(rawTx).rlpEncoded)
+  return buildHash('th', rawTx)
+}
+
+export default { calculateMinFee, calculateFee, unpackTx, unpackRawTx, buildTx, buildRawTx, validateParams, buildTxHash }

es/utils/crypto.js

@@ -106,7 +106,7 @@ export function addressFromDecimal (decimalAddress) {
 /**
  * Calculate 256bits Blake2b hash of `input`
  * @rtype (input: String) => hash: String
- * @param {String} input - Data to hash
+ * @param {String|Buffer} input - Data to hash
  * @return {Buffer} Hash
  */
 export function hash (input) {

test/unit/crypto.js

@@ -21,6 +21,7 @@ import { assert, expect } from 'chai'
 import * as Crypto from '../../es/utils/crypto'
 
 import { addressToHex, encodeBase58Check } from '../../es/utils/crypto'
+import { buildTxHash, unpackTx } from '../../es/tx/builder'
 
 // These keys are fixations for the encryption lifecycle tests and will
 // not be used for signing
@@ -34,6 +35,9 @@ const txBinary = Buffer.from(txBinaryAsArray)
 const signatureAsArray = [95, 146, 31, 37, 95, 194, 36, 76, 58, 49, 167, 156, 127, 131, 142, 248, 25, 121, 139, 109, 59, 243, 203, 205, 16, 172, 115, 143, 254, 236, 33, 4, 43, 46, 16, 190, 46, 46, 140, 166, 76, 39, 249, 54, 38, 27, 93, 159, 58, 148, 67, 198, 81, 206, 106, 237, 91, 131, 27, 14, 143, 178, 130, 2]
 const signature = Buffer.from(signatureAsArray)
 
+const txRaw = `tx_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'`
+const expectedHash = 'th_HZMNgTvEiyKeATpauJjjeWwZcyHapKG8bDgy2S1sCUEUQnbwK'
+
 describe('crypto', () => {
   describe('generateKeyPair', () => {
     it('generates an account key pair', () => {
@@ -142,4 +146,9 @@ describe('crypto', () => {
     const fromHexAddress = 'ak_' + encodeBase58Check(Buffer.from(hex.slice(2), 'hex'))
     fromHexAddress.should.be.equal(address)
   })
+  it('Can produce tx hash', () => {
+    const rlpEncodedTx = unpackTx(txRaw).rlpEncoded
+    buildTxHash(txRaw).should.be.equal(expectedHash)
+    buildTxHash(rlpEncodedTx).should.be.equal(expectedHash)
+  })
 })