perf: remove named links from object

This change was motivated by performance issues, but it also
really is cleaner to keep the IPLD objects lean and not cluttered
with IPFS related things.

BREAKING CHANGE: named links are no longer part of an object

Access to named links is only possible with calling `resolve()`.
Hence they are also not part of `tree()` anymore.

Named links are a feature of IPFS and only supported for
backwards compatibility, they are not really part of IPLD.

src/dag-node/dagNode.js

@@ -2,7 +2,6 @@
 
 const assert = require('assert')
 const withIs = require('class-is')
-const addNamedLink = require('./addNamedLink')
 const visibility = require('../visibility')
 
 class DAGNode {
@@ -18,13 +17,6 @@ class DAGNode {
     // Make sure we have a nice public API that can be used by an IPLD resolver
     visibility.hidePrivateFields(this)
     visibility.addEnumerableGetters(this, ['Data', 'Links'])
-
-    // Add getters for existing links by the name of the link
-    // This is how paths are traversed in IPFS. Links with names won't
-    // override existing fields like `data` or `links`.
-    links.forEach((link, position) => {
-      addNamedLink(this, link.Name, position)
-    })
   }
 
   toJSON () {

src/resolver.js

@@ -25,6 +25,17 @@ exports.resolve = (binaryBlob, path) => {
   while (parts.length) {
     const key = parts.shift()
     if (node[key] === undefined) {
+      // There might be a matching named link
+      for (const link of node.Links) {
+        if (link.Name === key) {
+          return {
+            value: link.Hash,
+            remainderPath: parts.join('/')
+          }
+        }
+      }
+
+      // There wasn't even a matching named link
       throw new Error(`Object has no property '${key}'`)
     }
 

test/dag-node-test.js

@@ -162,7 +162,6 @@ module.exports = (repo) => {
       expect(node1b.Links.length).to.equal(1)
       expect(node1b.Links[0].Tsize).to.eql(node2.size)
       expect(node1b.Links[0].Name).to.eql('banana')
-      expect(Object.keys(node1b)).to.include('banana')
     })
 
     it('addLink - add several links', async () => {
@@ -207,9 +206,7 @@ module.exports = (repo) => {
 
       const node1b = await DAGNode.addLink(node1a, link)
       expect(node1b.Links.length).to.eql(1)
-      expect(Object.keys(node1b)).to.include('banana')
       const node1c = DAGNode.rmLink(node1b, 'banana')
-      expect(Object.keys(node1c)).to.not.include('banana')
       expect(node1c.Links.length).to.eql(0)
       expect(node1c.toJSON()).to.eql(withoutLink)
     })
@@ -224,9 +221,7 @@ module.exports = (repo) => {
 
       const node1b = await DAGNode.addLink(node1a, link)
       expect(node1b.Links.length).to.eql(1)
-      expect(Object.keys(node1b)).to.include('banana')
       const node1c = DAGNode.rmLink(node1b, node1b.Links[0].Hash)
-      expect(Object.keys(node1c)).to.not.include('banana')
       expect(node1c.Links.length).to.eql(0)
       expect(node1c.toJSON()).to.eql(withoutLink)
     })

test/resolver.spec.js

@@ -157,8 +157,7 @@ describe('IPLD Format resolver (local)', () => {
         'Links/1/Name',
         'Links/1/Tsize',
         'Links/1/Hash',
-        'Data',
-        'named link'
+        'Data'
       ])
     })
   })
@@ -206,8 +205,7 @@ describe('IPLD Format resolver (local)', () => {
         'Links/1/Name',
         'Links/1/Tsize',
         'Links/1/Hash',
-        'Data',
-        'named link'
+        'Data'
       ])
     })
   })