Implement Node.traverse() to allow custom graph traversals.

lib/Node._coffee

@@ -502,3 +502,46 @@ module.exports = class Node extends PropertyContainer
 
         catch error
             throw adjustError error
+
+    traverse: (returnType, options={}, _) ->
+        try
+            type = encodeURIComponent returnType
+            traverseURL = @_data['traverse']?.replace '{returnType}', type
+
+            if not traverseURL
+                throw new Error 'Traverse not available.'
+
+            res = @_request.post
+                url: traverseURL
+                json: options
+            , _
+
+            if res.statusCode isnt status.OK
+                throw new Error "Unrecognized response code: #{res.statusCode}"
+
+            data = res.body
+
+            switch type
+              when 'node'
+                return data.map (data) => new Node @db, data
+              when 'relationship'
+                return data.map (data) =>
+                  if @self is data.start
+                    new Relationship @db, data, this, null
+                  else
+                    new Relationship @db, data, null, this
+              when 'path'
+                start = new Node this, {self: data.start}
+                end = new Node this, {self: data.end}
+                length = data.length
+                nodes = data.nodes.map (url) =>
+                  new Node this, {self: url}
+                relationships = data.relationships.map (url) =>
+                  new Relationship this, {self: url, type}
+                return new Path start, end, length, nodes, relationships
+              else
+                return null;
+
+        catch error
+            throw adjustError error
+

test/traverse._coffee

@@ -0,0 +1,75 @@
+{expect} = require 'chai'
+flows = require 'streamline/lib/util/flows'
+neo4j = require '..'
+
+db = new neo4j.GraphDatabase 'http://localhost:7474'
+
+# seed nodes into graph
+users = for i in [0..6]
+  db.createNode
+    name: "traversalTest#{i}"
+
+# node shortcut references
+user0 = users[0]
+user1 = users[1]
+user2 = users[2]
+user3 = users[3]
+user4 = users[4]
+user5 = users[5]
+user6 = users[6]
+
+@traverse = 
+
+  '(pre-req) save nodes': (_) ->
+    flows.collect _,
+      for user in users
+        user.save not _
+
+  '(pre-req) create relationships': (_) ->
+    createFollowRelationships = (i, _) ->
+      user = users[i]
+      i1 = (i + 1) % users.length
+      i2 = (i + 2) % users.length
+      i3 = (i + 3) % users.length
+      flows.collect _, [
+        user.createRelationshipTo users[i1], 'traverse_follows', {}, not _
+        user.createRelationshipTo users[i2], 'traverse_follows', {}, not _
+        user.createRelationshipTo users[i3], 'traverse_follows', {}, not _
+      ]
+
+    flows.collect _,
+      for user, i in users
+        createFollowRelationships i, not _
+
+  'traverse connected nodes': (_) ->
+    nodes = user0.traverse 'node', {
+      order: 'breadth_first',
+      return_filter: {
+        body: """position.endNode().getProperty('name').contains('t')""",
+        language: 'javascript'
+      },
+      prune_evaluator: {
+        body: 'none',
+        language: 'builtin'
+      },
+      uniqueness: 'node_global',
+      relationships: [{
+        direction: 'all',
+        type: 'traverse_follows'
+      }],
+      max_depth: 3
+    }, _
+
+    expect(nodes).to.exist
+    expect(nodes).to.be.an 'array'
+    expect(nodes).to.have.length 7
+    expect(nodes[0]).to.exist;
+
+    nodes.forEach (node) =>
+      expect(node.data).to.be.an 'object'
+      expect(node.data.name).to.contain 't'
+
+for name, test of @traverse
+  do (name, test) =>
+    @traverse[name] = (_) ->
+      test _