fix: make addLink() synchronous

BREAKING CHANGE: It's no longer possible to pass a `DAGNode` into `addLink()`.

Intead of passing in a `DAGNode` into `addLink()`, convert that node into
a `DAGLink` via `toDAGLink()`.

Example:

Prior to this change:

    const node = new DAGNode('some data')
    const node2 = new DAGNode('use that as link')
    await DAGNode.addLink(node, node2)

Now:

    const node = new DAGNode('some data')
    const node2 = new DAGNode('use that as link')
    DAGNode.addLink(node, await node2.toDAGLink())

Closes #128.

README.md

@@ -36,6 +36,7 @@
     - [`node.size`](#nodesize)
     - [`node.toJSON()`](#nodetojson)
     - [`node.toString()`](#nodetostring)
+    - [`node.toDAGLink(options)`](#nodetodaglinkoptions)
   - [DAGLink functions](#daglink-functions)
     - [DAGLink constructor](#daglink-constructor)
   - [DAGLink instance methods and properties](#daglink-instance-methods-and-properties)
@@ -93,7 +94,7 @@ const link = {
   Tsize: 42
 }
 
-await DAGNode.addLink(node, link)
+DAGNode.addLink(node, link)
 console.log('with link', node.toJSON())
 
 DAGNode.rmLink(nodeA, 'I am a link')
@@ -154,7 +155,7 @@ const link = {
   Hash: <cid> // can be a String CID, CID buffer or CID object
 }
 
-await DAGNode.addLink(node, link)
+DAGNode.addLink(node, link)
 ```
 
 #### rmLink(node, nameOrCid)
@@ -187,6 +188,19 @@ Size of the node, in bytes
 
 #### `node.toString()`
 
+#### `node.toDAGLink()`
+
+- `options` - (optional) type: Object. Currently the only option is `name` to specify a named link.
+
+Converts a `DAGNode` into a `DAGLink`.
+
+```JavaScript
+const node = new DAGNode('some data')
+const link = node.toDAGLink()
+// Named link
+const link = node.toDAGLink({ name: 'name-of-the-link' })
+```
+
 
 ### DAGLink functions
 

src/dag-node/addLink.js

@@ -1,31 +1,26 @@
 'use strict'
 
 const sortLinks = require('./sortLinks')
-const toDAGLink = require('./toDagLink')
 const DAGLink = require('../dag-link')
 const DAGNode = require('./index')
 
-// Intentionally keeping the `async` to signal that it may return a promise
-// eslint-disable-next-line require-await
-const asDAGLink = async (link) => {
+const asDAGLink = (link) => {
   if (DAGLink.isDAGLink(link)) {
     // It's a DAGLink instance
     // no need to do anything
     return link
   }
 
   if (DAGNode.isDAGNode(link)) {
-    // It's a DAGNode instance
-    // convert to link
-    return toDAGLink(link, {})
+    throw new Error('Link must be a DAGLink or DAGLink-like. Convert the DAGNode into a DAGLink via `node.toDAGLink()`.')
   }
 
   // It's a Object with name, multihash/hash/cid and size
   return new DAGLink(link.Name || link.name, link.Tsize || link.size, link.Hash || link.multihash || link.hash || link.cid)
 }
 
-const addLink = async (node, link) => {
-  const dagLink = await asDAGLink(link)
+const addLink = (node, link) => {
+  const dagLink = asDAGLink(link)
   node._links.push(dagLink)
   node._links = sortLinks(node._links)
 }

src/dag-node/dagNode.js

@@ -5,6 +5,7 @@ const sortLinks = require('./sortLinks')
 const visibility = require('../visibility')
 const DAGLink = require('../dag-link/dagLink')
 const { serializeDAGNode } = require('../serialize.js')
+const toDAGLink = require('./toDagLink')
 
 class DAGNode {
   constructor (data, links = [], serializedSize = 0) {
@@ -57,6 +58,11 @@ class DAGNode {
     return `DAGNode <data: "${this.Data.toString('base64')}", links: ${this.Links.length}, size: ${this.size}>`
   }
 
+  // @returns {Promise.<DAGLink>}
+  toDAGLink (options) {
+    return toDAGLink(this, options)
+  }
+
   get size () {
     if (this._size === undefined) {
       this._size = this._links.reduce((sum, l) => sum + l.Tsize, this._serializedSize)

src/dag-node/toDagLink.js

@@ -1,14 +1,15 @@
 'use strict'
 
-const DAGLink = require('./../dag-link/dagLink')
-const { cid, serialize } = require('../util')
+const DAGLink = require('../dag-link/dagLink')
+const { serializeDAGNode } = require('../serialize')
+const genCid = require('../genCid')
 
 /*
  * toDAGLink converts a DAGNode to a DAGLink
  */
 const toDAGLink = async (node, options = {}) => {
-  const serialized = serialize(node)
-  const nodeCid = await cid(serialized)
+  const serialized = serializeDAGNode(node)
+  const nodeCid = await genCid.cid(serialized)
   return new DAGLink(options.name || '', serialized.length, nodeCid)
 }
 

src/genCid.js

@@ -0,0 +1,32 @@
+'use strict'
+
+const CID = require('cids')
+const multicodec = require('multicodec')
+const multihashing = require('multihashing-async')
+
+exports = module.exports
+
+exports.codec = multicodec.DAG_PB
+exports.defaultHashAlg = multicodec.SHA2_256
+
+/**
+ * Calculate the CID of the binary blob.
+ *
+ * @param {Object} binaryBlob - Encoded IPLD Node
+ * @param {Object} [userOptions] - Options to create the CID
+ * @param {number} [userOptions.cidVersion=1] - CID version number
+ * @param {string} [UserOptions.hashAlg] - Defaults to the defaultHashAlg of the format
+ * @returns {Promise.<CID>}
+ */
+const cid = async (binaryBlob, userOptions) => {
+  const defaultOptions = { cidVersion: 1, hashAlg: exports.defaultHashAlg }
+  const options = Object.assign(defaultOptions, userOptions)
+
+  const multihash = await multihashing(binaryBlob, options.hashAlg)
+  const codecName = multicodec.print[exports.codec]
+  const cid = new CID(options.cidVersion, codecName, multihash)
+
+  return cid
+}
+
+exports.cid = cid

src/util.js

@@ -1,18 +1,16 @@
 'use strict'
 
-const CID = require('cids')
 const protons = require('protons')
 const proto = protons(require('./dag.proto'))
 const DAGLink = require('./dag-link/dagLink')
 const DAGNode = require('./dag-node/dagNode')
-const multicodec = require('multicodec')
-const multihashing = require('multihashing-async')
 const { serializeDAGNode, serializeDAGNodeLike } = require('./serialize')
+const genCid = require('./genCid')
 
 exports = module.exports
 
-exports.codec = multicodec.DAG_PB
-exports.defaultHashAlg = multicodec.SHA2_256
+exports.codec = genCid.codec
+exports.defaultHashAlg = genCid.defaultHashAlg
 
 /**
  * Calculate the CID of the binary blob.
@@ -23,15 +21,8 @@ exports.defaultHashAlg = multicodec.SHA2_256
  * @param {string} [UserOptions.hashAlg] - Defaults to the defaultHashAlg of the format
  * @returns {Promise.<CID>}
  */
-const cid = async (binaryBlob, userOptions) => {
-  const defaultOptions = { cidVersion: 1, hashAlg: exports.defaultHashAlg }
-  const options = Object.assign(defaultOptions, userOptions)
-
-  const multihash = await multihashing(binaryBlob, options.hashAlg)
-  const codecName = multicodec.print[exports.codec]
-  const cid = new CID(options.cidVersion, codecName, multihash)
-
-  return cid
+const cid = (binaryBlob, userOptions) => {
+  return genCid.cid(binaryBlob, userOptions)
 }
 
 /**

test/dag-node-test.js

@@ -9,7 +9,6 @@ chai.use(dirtyChai)
 const dagPB = require('../src')
 const DAGLink = dagPB.DAGLink
 const DAGNode = dagPB.DAGNode
-const toDAGLink = require('../src/dag-node/toDagLink')
 const isNode = require('detect-node')
 const multihash = require('multihashes')
 const multicodec = require('multicodec')
@@ -126,7 +125,7 @@ module.exports = (repo) => {
     it('addLink by DAGNode', async () => {
       const node1 = new DAGNode(Buffer.from('1'))
       const node2 = new DAGNode(Buffer.from('2'))
-      await DAGNode.addLink(node1, node2)
+      DAGNode.addLink(node1, await node2.toDAGLink())
       expect(node1.Links.length).to.equal(1)
       expect(node1.Links[0].Tsize).to.eql(node2.size)
       expect(node1.Links[0].Name).to.be.eql('')
@@ -135,8 +134,8 @@ module.exports = (repo) => {
     it('addLink by DAGLink', async () => {
       const node1 = new DAGNode(Buffer.from('1'))
       const node2 = new DAGNode(Buffer.from('2'))
-      const link = await toDAGLink(node2)
-      await DAGNode.addLink(node1, link)
+      const link = await node2.toDAGLink()
+      DAGNode.addLink(node1, link)
       expect(node1.Links.length).to.equal(1)
       expect(node1.Links[0].Tsize).to.eql(node2.size)
       expect(node1.Links[0].Name).to.be.eql('')
@@ -145,9 +144,9 @@ module.exports = (repo) => {
     it('addLink by object', async () => {
       const node1 = new DAGNode(Buffer.from('1'))
       const node2 = new DAGNode(Buffer.from('2'))
-      const link = await toDAGLink(node2)
+      const link = await node2.toDAGLink()
       const linkObject = link.toJSON()
-      await DAGNode.addLink(node1, linkObject)
+      DAGNode.addLink(node1, linkObject)
       expect(node1.Links.length).to.equal(1)
       expect(node1.Links[0].Tsize).to.eql(node2.size)
       expect(node1.Links[0].Name).to.be.eql('')
@@ -156,9 +155,9 @@ module.exports = (repo) => {
     it('addLink by name', async () => {
       const node1 = new DAGNode(Buffer.from('1'))
       const node2 = new DAGNode(Buffer.from('2'))
-      const link = await toDAGLink(node2, { name: 'banana' })
+      const link = await node2.toDAGLink({ name: 'banana' })
       expect(node1.Links.length).to.equal(0)
-      await DAGNode.addLink(node1, link)
+      DAGNode.addLink(node1, link)
       expect(node1.Links.length).to.equal(1)
       expect(node1.Links[0].Tsize).to.eql(node2.size)
       expect(node1.Links[0].Name).to.eql('banana')
@@ -169,29 +168,27 @@ module.exports = (repo) => {
       expect(node1.Links.length).to.equal(0)
 
       const node2 = new DAGNode(Buffer.from('2'))
-      await DAGNode.addLink(node1, node2)
+      DAGNode.addLink(node1, await node2.toDAGLink())
       expect(node1.Links.length).to.equal(1)
 
       const node3 = new DAGNode(Buffer.from('3'))
-      await DAGNode.addLink(node1, node3)
+      DAGNode.addLink(node1, await node3.toDAGLink())
       expect(node1.Links.length).to.equal(2)
     })
 
     it('addLink by DAGNode.Links', async () => {
       const linkName = 'link-name'
       const remote = new DAGNode(Buffer.from('2'))
       const source = new DAGNode(Buffer.from('1'))
-      await DAGNode.addLink(
+      DAGNode.addLink(
         source,
-        await toDAGLink(remote, {
-          name: linkName
-        })
+        await remote.toDAGLink({ name: linkName })
       )
 
       expect(source.Links.length).to.equal(1)
 
       const target = new DAGNode(null, [], 0)
-      await DAGNode.addLink(target, source.Links[0])
+      DAGNode.addLink(target, source.Links[0])
 
       expect(target.Links.length).to.equal(1)
       expect(target.Links[0].Tsize).to.eql(remote.size)
@@ -204,9 +201,9 @@ module.exports = (repo) => {
       const withoutLink = node1.toJSON()
 
       const node2 = new DAGNode(Buffer.from('2'))
-      const link = await toDAGLink(node2, { name: 'banana' })
+      const link = await node2.toDAGLink({ name: 'banana' })
 
-      await DAGNode.addLink(node1, link)
+      DAGNode.addLink(node1, link)
       expect(node1.Links.length).to.eql(1)
       DAGNode.rmLink(node1, 'banana')
       expect(node1.Links.length).to.eql(0)
@@ -219,9 +216,9 @@ module.exports = (repo) => {
       const withoutLink = node1.toJSON()
 
       const node2 = new DAGNode(Buffer.from('2'))
-      const link = await toDAGLink(node2, { name: 'banana' })
+      const link = await node2.toDAGLink({ name: 'banana' })
 
-      await DAGNode.addLink(node1, link)
+      DAGNode.addLink(node1, link)
       expect(node1.Links.length).to.eql(1)
       DAGNode.rmLink(node1, node1.Links[0].Hash)
       expect(node1.Links.length).to.eql(0)