From 6e28d3e6f52d2d436cee81fbdfc8f1f58a2e1b12 Mon Sep 17 00:00:00 2001
From: Richard Schneider <makaretu@gmail.com>
Date: Sat, 23 Jun 2018 00:27:45 +1200
Subject: [PATCH] feat: add defaultHashAlg (#17)

See https://github.com/ipld/interface-ipld-format/issues/37
---
 src/resolver.js       | 1 +
 src/util.js           | 4 +++-
 test/resolver.spec.js | 5 +++++
 3 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/resolver.js b/src/resolver.js
index dd9e177..8470399 100644
--- a/src/resolver.js
+++ b/src/resolver.js
@@ -133,6 +133,7 @@ const resolveField = (dagNode, field) => {
 
 module.exports = {
   multicodec: 'bitcoin-block',
+  defaultHashAlg: 'dbl-sha2-256',
   resolve: resolve,
   tree: tree
 }
diff --git a/src/util.js b/src/util.js
index cd61c9c..d536357 100644
--- a/src/util.js
+++ b/src/util.js
@@ -87,7 +87,9 @@ const cid = (dagNode, callback) => {
 
 // Convert a Bitcoin hash (as Buffer) to a CID
 const hashToCid = (hash) => {
-  const multihash = multihashes.encode(hash, 'dbl-sha2-256')
+  // avoid deadly embrace between resolver and util
+  const defaultHashAlg = require('./resolver').defaultHashAlg
+  const multihash = multihashes.encode(hash, defaultHashAlg)
   const cidVersion = 1
   const cid = new CID(cidVersion, 'bitcoin-block', multihash)
   return cid
diff --git a/test/resolver.spec.js b/test/resolver.spec.js
index 3e19020..75ac5b0 100644
--- a/test/resolver.spec.js
+++ b/test/resolver.spec.js
@@ -139,6 +139,11 @@ describe('IPLD format resolver API properties', () => {
     expect(IpldBitcoin.resolver.multicodec).to.equal('bitcoin-block')
     done()
   })
+
+  it('should have `defaultHashAlg` defined correctly', (done) => {
+    expect(IpldBitcoin.resolver.defaultHashAlg).to.equal('dbl-sha2-256')
+    done()
+  })
 })
 
 const verifyPath = (block, path, expected, done) => {