feat: remove DAGNode.create()

BREAKING CHANGE: DAGNode.create() is removed

Instead of `DAGNode.create()`, please use `new DAGNode()` instead. It
takes the same parameters and is compatible to `create()`.

Example:

Prior to this change:

    const node = DAGNode.create('some data', links)

Now:

    const node = new DAGNode('some data', links)

Closes #132.

README.md

@@ -27,7 +27,7 @@
     - [Add and remove a Link](#add-and-remove-a-link)
 - [API](#api)
   - [DAGNode functions](#dagnode-functions)
-    - [DAGNode.create(data, links)](#dagnodecreatedata-links)
+    - [DAGNode constructor](#dagnode-constructor)
     - [addLink(node, link)](#addlinknode-link)
     - [rmLink(node, nameOrCid)](#rmlinknode-nameorcid)
   - [DAGNode instance methods and properties](#dagnode-instance-methods-and-properties)
@@ -65,7 +65,6 @@
 ```JavaScript
 const dagPB = require('ipld-dag-pb')
 
-dagPB.DAGNode.create  // create a DAGNode
 dagPB.DAGNode.addLink // add a Link to a DAGNode, creating a new one
 dagPB.DAGNode.rmLink  // remove a Link to a DAGNode, creating a new one
 
@@ -79,10 +78,10 @@ dagPB.util
 #### Create a DAGNode
 
 ```JavaScript
-const node1 = DAGNode.create(Buffer.from('some data'))
+const node1 = new DAGNode(Buffer.from('some data'))
 
 // node2 will have the same data as node1
-const node2 = DAGNode.create('some data')
+const node2 = new DAGNode('some data')
 ```
 
 #### Add and remove a Link
@@ -114,15 +113,16 @@ const dagPB = require('ipld-dag-pb')
 const DAGNode = dagPB.DAGNode
 ```
 
-#### DAGNode.create(data, links)
+#### DAGNode constructor
 
 - `data` - type: Buffer
-- `links`- type: Array of DAGLink instances or Array of DAGLink instances in its json format (link.toJSON)
+- `links`- (optional) type: Array of DAGLink instances or Array of DAGLink instances in its json format (link.toJSON)
+- `serializedSize`- (optional) type: Number of bytes the serialized node has. If none is given, it will automatically be calculated.
 
 Create a DAGNode.
 
 ```JavaScript
-const dagNode = DAGNode.create('data', links)
+const dagNode = new DAGNode('data', links)
 ```
 
 links can be a single or an array of DAGLinks instances or objects with the following pattern

src/dag-node/addLink.js

@@ -1,7 +1,7 @@
 'use strict'
 
-const sort = require('stable')
-const { linkSort, toDAGLink } = require('./util')
+const sortLinks = require('./sortLinks')
+const toDAGLink = require('./toDagLink')
 const DAGLink = require('../dag-link')
 const DAGNode = require('./index')
 
@@ -27,7 +27,7 @@ const asDAGLink = async (link) => {
 const addLink = async (node, link) => {
   const dagLink = await asDAGLink(link)
   node._links.push(dagLink)
-  node._links = sort(node._links, linkSort)
+  node._links = sortLinks(node._links)
 }
 
 module.exports = addLink

src/dag-node/dagNode.js

@@ -1,16 +1,38 @@
 'use strict'
 
-const assert = require('assert')
 const withIs = require('class-is')
+const sortLinks = require('./sortLinks')
 const visibility = require('../visibility')
+const DAGLink = require('../dag-link/dagLink')
+const { serializeDAGNode } = require('../serialize.js')
 
 class DAGNode {
-  constructor (data, links, serializedSize) {
-    if (serializedSize !== 0) {
-      assert(serializedSize, 'A DAGNode requires it\'s serialized size')
+  constructor (data, links = [], serializedSize = 0) {
+    if (!data) {
+      data = Buffer.alloc(0)
+    }
+    if (typeof data === 'string') {
+      data = Buffer.from(data)
+    }
+    if (!Buffer.isBuffer(data)) {
+      throw new Error('Passed \'data\' is not a buffer or a string!')
+    }
+
+    links = links.map((link) => {
+      return DAGLink.isDAGLink(link)
+        ? link
+        : DAGLink.util.createDagLinkFromB58EncodedHash(link)
+    })
+    links = sortLinks(links)
+
+    if (serializedSize === 0) {
+      serializedSize = serializeDAGNode({
+        Data: data,
+        Links: links
+      }).length
     }
 
-    this._data = data || Buffer.alloc(0)
+    this._data = data
     this._links = links
     this._serializedSize = serializedSize
 

src/dag-node/index.js

@@ -1,6 +1,5 @@
 'use strict'
 
 exports = module.exports = require('./dagNode')
-exports.create = require('./create')
 exports.addLink = require('./addLink')
 exports.rmLink = require('./rmLink')

src/dag-node/sortLinks.js

@@ -0,0 +1,13 @@
+'use strict'
+
+const sort = require('stable')
+
+const linkSort = (a, b) => {
+  return Buffer.compare(a.nameAsBuffer, b.nameAsBuffer)
+}
+
+const sortLinks = (links) => {
+  return sort(links, linkSort)
+}
+
+module.exports = sortLinks

src/dag-node/util.js → src/dag-node/toDagLink.js

@@ -1,16 +1,7 @@
 'use strict'
 
 const DAGLink = require('./../dag-link/dagLink')
-const {
-  cid,
-  serialize
-} = require('../util')
-
-exports = module.exports
-
-function linkSort (a, b) {
-  return Buffer.compare(a.nameAsBuffer, b.nameAsBuffer)
-}
+const { cid, serialize } = require('../util')
 
 /*
  * toDAGLink converts a DAGNode to a DAGLink
@@ -21,5 +12,4 @@ const toDAGLink = async (node, options = {}) => {
   return new DAGLink(options.name || '', serialized.length, nodeCid)
 }
 
-exports.linkSort = linkSort
-exports.toDAGLink = toDAGLink
+module.exports = toDAGLink

src/serialize.js

@@ -0,0 +1,64 @@
+'use strict'
+
+const protons = require('protons')
+const proto = protons(require('./dag.proto.js'))
+const DAGLink = require('./dag-link/dagLink')
+
+exports = module.exports
+
+const toProtoBuf = (node) => {
+  const pbn = {}
+
+  if (node.Data && node.Data.length > 0) {
+    pbn.Data = node.Data
+  } else {
+    // NOTE: this has to be null in order to match go-ipfs serialization
+    // `null !== new Buffer(0)`
+    pbn.Data = null
+  }
+
+  if (node.Links && node.Links.length > 0) {
+    pbn.Links = node.Links
+      .map((link) => ({
+        Hash: link.Hash.buffer,
+        Name: link.Name,
+        Tsize: link.Tsize
+      }))
+  } else {
+    pbn.Links = null
+  }
+
+  return pbn
+}
+
+/**
+ * Serialize internal representation into a binary PB block.
+ *
+ * @param {Object} node - Internal representation of a CBOR block
+ * @returns {Buffer} - The encoded binary representation
+ */
+const serializeDAGNode = (node) => {
+  const data = node.Data
+  const links = node.Links || []
+
+  const serialized = proto.PBNode.encode(toProtoBuf({
+    Data: data,
+    Links: links
+  }))
+
+  return serialized
+}
+
+// Serialize an object where the `Links` might not be a `DAGLink` instance yet
+const serializeDAGNodeLike = (data, links = []) => {
+  const node = { Data: data }
+  node.Links = links.map((link) => {
+    return DAGLink.isDAGLink(link)
+      ? link
+      : DAGLink.util.createDagLinkFromB58EncodedHash(link)
+  })
+  return serializeDAGNode(node)
+}
+
+exports.serializeDAGNode = serializeDAGNode
+exports.serializeDAGNodeLike = serializeDAGNodeLike

src/util.js

@@ -7,6 +7,7 @@ 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')
 
 exports = module.exports
 
@@ -40,22 +41,11 @@ const cid = async (binaryBlob, userOptions) => {
  * @returns {Buffer} - The encoded binary representation
  */
 const serialize = (node) => {
-  const data = node.Data
-  let links = node.Links || []
-
-  // If the node is not an instance of a DAGNode, the link.hash might be a Base58 encoded string; decode it
-  if (!DAGNode.isDAGNode(node) && links) {
-    links = links.map((link) => {
-      return DAGLink.isDAGLink(link) ? link : DAGLink.util.createDagLinkFromB58EncodedHash(link)
-    })
+  if (DAGNode.isDAGNode(node)) {
+    return serializeDAGNode(node)
+  } else {
+    return serializeDAGNodeLike(node.Data, node.Links)
   }
-
-  const serialized = proto.PBNode.encode(toProtoBuf({
-    Data: data,
-    Links: links
-  }))
-
-  return serialized
 }
 
 /**
@@ -76,30 +66,6 @@ const deserialize = (buffer) => {
   return new DAGNode(data, links, buffer.length)
 }
 
-function toProtoBuf (node) {
-  const pbn = {}
-
-  if (node.Data && node.Data.length > 0) {
-    pbn.Data = node.Data
-  } else {
-    // NOTE: this has to be null in order to match go-ipfs serialization `null !== new Buffer(0)`
-    pbn.Data = null
-  }
-
-  if (node.Links && node.Links.length > 0) {
-    pbn.Links = node.Links
-      .map((link) => ({
-        Hash: link.Hash.buffer,
-        Name: link.Name,
-        Tsize: link.Tsize
-      }))
-  } else {
-    pbn.Links = null
-  }
-
-  return pbn
-}
-
 exports.serialize = serialize
 exports.deserialize = deserialize
 exports.cid = cid