From 72c55e711da29e41da660e804aa1247794ee43b5 Mon Sep 17 00:00:00 2001
From: Chris Pettitt <cpettitt@gmail.com>
Date: Tue, 9 Sep 2014 09:26:39 -0700
Subject: [PATCH] Performance improvements

---
 lib/graph.js | 35 +++++++++++++++++++++--------------
 1 file changed, 21 insertions(+), 14 deletions(-)

diff --git a/lib/graph.js b/lib/graph.js
index bafc12b8..9e63edc6 100644
--- a/lib/graph.js
+++ b/lib/graph.js
@@ -35,13 +35,16 @@ function Graph(opts) {
   this._nodes = {};
 
   // v -> edgeObj
-  this._in= {};
+  this._in = {};
 
   // v -> edgeObj
-  this._out= {};
+  this._out = {};
+
+  // e -> edgeObj
+  this._edgeObjs = {};
 
   // e -> attrs
-  this._edges = {};
+  this._edgeAttrs = {};
 }
 
 /* Number of nodes in the graph. Should only be changed by the implementation. */
@@ -131,7 +134,7 @@ Graph.prototype.edgeCount = function() {
 };
 
 Graph.prototype.allEdges = function() {
-  return _.map(_.keys(this._edges), edgeIdToObj);
+  return _.values(this._edgeObjs);
 };
 
 Graph.prototype.path = function() {
@@ -150,7 +153,7 @@ Graph.prototype.edge = function(v, w, name) {
   var e = (arguments.length === 1
               ? edgeObjToId(this.isDirected, arguments[0])
               : edgeArgsToId(this.isDirected, v, w, name));
-  var edge = this._edges[e];
+  var edge = this._edgeAttrs[e];
   if (edge) {
     return edge;
   }
@@ -169,10 +172,13 @@ Graph.prototype.edge = function(v, w, name) {
     this.node(v);
     this.node(w);
 
-    edge = _.merge({}, this.edgeAttrDefs);
-    this._edges[e] = edge;
-    this._out[v][e] = true;
-    this._in[w][e] = true;
+    edge = this._edgeAttrs[e] = _.merge({}, this.edgeAttrDefs);
+
+    var edgeObj = edgeIdToObj(e);
+    Object.freeze(edgeObj);
+    this._edgeObjs[e] = edgeObj;
+    this._out[v][e] = edgeObj;
+    this._in[w][e] = edgeObj;
     this._edgeCount++;
     return edge;
   }
@@ -182,14 +188,14 @@ Graph.prototype.hasEdge = function(v, w, name) {
   var e = (arguments.length === 1
             ? edgeObjToId(this.isDirected, arguments[0])
             : edgeArgsToId(this.isDirected, v, w, name));
-  return _.has(this._edges, e);
+  return _.has(this._edgeAttrs, e);
 };
 
 Graph.prototype.removeEdge = function(v, w, name) {
   var e = (arguments.length === 1
             ? edgeObjToId(this.isDirected, arguments[0])
             : edgeArgsToId(this.isDirected, v, w, name));
-  if (_.has(this._edges, e)) {
+  if (_.has(this._edgeAttrs, e)) {
     if (arguments.length === 1) {
       v = arguments[0].v;
       w = arguments[0].w;
@@ -197,7 +203,8 @@ Graph.prototype.removeEdge = function(v, w, name) {
     }
     delete this._out[v][e];
     delete this._in[w][e];
-    delete this._edges[e];
+    delete this._edgeAttrs[e];
+    delete this._edgeObjs[e];
     this._edgeCount--;
   }
 };
@@ -205,14 +212,14 @@ Graph.prototype.removeEdge = function(v, w, name) {
 Graph.prototype.inEdges = function(v) {
   var inV = this._in[v];
   if (inV) {
-    return _.map(_.keys(inV), edgeIdToObj);
+    return _.values(inV);
   }
 };
 
 Graph.prototype.outEdges = function(v) {
   var outV = this._out[v];
   if (outV) {
-    return _.map(_.keys(outV), edgeIdToObj);
+    return _.values(outV);
   }
 };