feat: expose cid property on DAGLinks and DAGNodes

Implements the change proposed in #81 (comment)

src/dag-link/index.js

@@ -56,6 +56,14 @@ class DAGLink {
   set multihash (multihash) {
     throw new Error("Can't set property: 'multihash' is immutable")
   }
+
+  get cid () {
+    return this._cid
+  }
+
+  set cid (cid) {
+    throw new Error("Can't set property: 'cid' is immutable")
+  }
 }
 
 exports = module.exports = withIs(DAGLink, { className: 'DAGLink', symbolName: '@ipld/js-ipld-dag-pb/daglink' })

src/dag-node/index.js

@@ -75,6 +75,14 @@ class DAGNode {
   set multihash (multihash) {
     throw new Error("Can't set property: 'multihash' is immutable")
   }
+
+  get cid () {
+    return this._cid
+  }
+
+  set cid (cid) {
+    throw new Error("Can't set property: 'cid' is immutable")
+  }
 }
 
 exports = module.exports = withIs(DAGNode, { className: 'DAGNode', symbolName: '@ipld/js-ipld-dag-pb/dagnode' })

test/dag-link-test.js

@@ -53,5 +53,22 @@ module.exports = (repo) => {
 
       expect(link.toString()).to.equal('DAGLink <QmXg9Pp2ytZ14xgmQjYEiHjVjMFXzCVVEcRTWJBmLgR39U - name: "hello", size: 3>')
     })
+
+    it('exposes a CID', () => {
+      const cid = 'QmXg9Pp2ytZ14xgmQjYEiHjVjMFXzCVVEcRTWJBmLgR39U'
+      const link = new DAGLink('hello', 3, cid)
+      expect(link.cid.toBaseEncodedString()).to.equal(cid)
+    })
+
+    it('has an immutable CID', () => {
+      const link = new DAGLink('hello', 3, 'QmXg9Pp2ytZ14xgmQjYEiHjVjMFXzCVVEcRTWJBmLgR39U')
+
+      try {
+        link.cid = 'foo'
+        throw new Error('Should not be able to update CID')
+      } catch (error) {
+        expect(error.message).to.include("'cid' is immutable")
+      }
+    })
   })
 }

test/dag-node-test.js

@@ -663,5 +663,27 @@ module.exports = (repo) => {
         })
       })
     }).timeout(6000)
+
+    it('exposes a CID', (done) => {
+      DAGNode.create(Buffer.from('hello world'), (err, node) => {
+        expect(err).to.not.exist()
+        expect(node.cid.toBaseEncodedString()).to.equal('QmU1Sq1B7RPQD2XcQNLB58qJUyJffVJqihcxmmN1STPMxf')
+        done()
+      })
+    })
+
+    it('has an immutable CID', (done) => {
+      DAGNode.create(Buffer.from('hello world'), (err, node) => {
+        expect(err).to.not.exist()
+
+        try {
+          node.cid = 'foo'
+          throw new Error('Should not be able to update CID')
+        } catch (error) {
+          expect(error.message).to.include("'cid' is immutable")
+          done()
+        }
+      })
+    })
   })
 }