Add mainnet/testnet version byte helpers

README.md

@@ -34,10 +34,9 @@ Pass in version bytes for a different network:
 
 ```js
 const createXpub = require('create-xpub');
-const TESTNET = 0x043587CF;
 
 const tpub = createXpub({
-  networkVersion: TESTNET,
+  networkVersion: createXpub.testnet,
   depth: 3,
   childNumber: 2147483648,
   chainCode: '84cf7d9029cdd9fcadbb3717fd92ec0db7d7d9787c57c13c08fc887c389b566b',
@@ -99,6 +98,14 @@ Default: `undefined`
 
 The public key in compressed or uncompressed form.
 
+### createXpub.mainnet
+
+Mainnet (xpub) version bytes: `0x0488B21E`
+
+### createXpub.testnet
+
+Testnet (tpub) version bytes: `0x043587CF`
+
 ## License
 
 MIT © Luke Childs

src/index.js

@@ -3,6 +3,7 @@ const bs58check = require('bs58check');
 const {sha256, ripemd160} = require('hash.js');
 
 const XPUB = 0x0488B21E;
+const TPUB = 0x043587CF;
 
 const compressPublicKey = publicKey => {
 	if (publicKey.startsWith('02') || publicKey.startsWith('03')) {
@@ -55,4 +56,7 @@ const createXpub = ({networkVersion = XPUB, depth, childNumber, chainCode, publi
 	return bs58check.encode(xpub);
 };
 
+createXpub.mainnet = XPUB;
+createXpub.testnet = TPUB;
+
 module.exports = createXpub;

test/unit.js

@@ -1,7 +1,6 @@
 import test from 'ava';
 import createXpub from '..';
 
-const TPUB = 0x043587CF;
 const xpubTestParams = {
 	depth: 3,
 	childNumber: 2147483648,
@@ -23,7 +22,7 @@ test('createXpub is serialised correctly', t => {
 test('Different network version bytes can be passed in', t => {
 	const tpub = createXpub({
 		...xpubTestParams,
-		networkVersion: TPUB
+		networkVersion: createXpub.testnet
 	});
 	t.is(tpub, expectedTpub);
 });