feat: add defaultHashAlg (#65)

See ipld/interface-ipld-format#37

Author: richardschneider

src/resolver.js

@@ -6,6 +6,7 @@ const traverse = require('traverse')
 exports = module.exports
 
 exports.multicodec = 'dag-cbor'
+exports.defaultHashAlg = 'sha2-256'
 
 /*
  * resolve: receives a path and a binary blob and returns the value on path,

src/util.js

@@ -111,7 +111,7 @@ exports.deserialize = (data, callback) => {
 exports.cid = (dagNode, callback) => {
   waterfall([
     (cb) => exports.serialize(dagNode, cb),
-    (serialized, cb) => multihashing(serialized, 'sha2-256', cb),
+    (serialized, cb) => multihashing(serialized, resolver.defaultHashAlg, cb),
     (mh, cb) => cb(null, new CID(1, resolver.multicodec, mh))
   ], callback)
 }

test/resolver.spec.js

@@ -53,6 +53,10 @@ describe('IPLD format resolver (local)', () => {
     expect(resolver.multicodec).to.equal('dag-cbor')
   })
 
+  it('defaultHashAlg is sha2-256', () => {
+    expect(resolver.defaultHashAlg).to.equal('sha2-256')
+  })
+
   describe('empty node', () => {
     describe('resolver.resolve', () => {
       it('root', (done) => {