From 850e7d6568129736fc231c61ecc0584f41f2a0e4 Mon Sep 17 00:00:00 2001
From: Tom MacWright <tom@macwright.org>
Date: Wed, 9 Jan 2013 13:45:04 -0500
Subject: [PATCH] Optimize difference and parentWays

---
 js/id/graph/graph.js  | 15 ++++++++++-----
 js/id/renderer/map.js | 14 ++++++++------
 2 files changed, 18 insertions(+), 11 deletions(-)

diff --git a/js/id/graph/graph.js b/js/id/graph/graph.js
index 519dc9d29..0fb618627 100644
--- a/js/id/graph/graph.js
+++ b/js/id/graph/graph.js
@@ -46,15 +46,20 @@ iD.Graph.prototype = {
     },
 
     parentWays: function(id) {
-        // This is slow and a bad hack.
-        return _.filter(this.entities, function(e) {
-            return e && e.type === 'way' && e.nodes.indexOf(id) !== -1;
-        });
+        var o = [];
+        for (var i in this.entities) {
+            if (this.entities[i] &&
+                this.entities[i].type === 'way' &&
+                this.entities[i].nodes.indexOf(id) !== -1) {
+                o.push(this.entities[i]);
+            }
+        }
+        return o;
     },
 
     parentRelations: function(id) {
         // This is slow and a bad hack.
-        return _.filter(this.entities, function(e) {
+        return _.filter(this.entities, function buildParentRelations(e) {
             return e && e.type === 'relation' &&
                 _.pluck(e.members, 'id').indexOf(id) !== -1;
         });
diff --git a/js/id/renderer/map.js b/js/id/renderer/map.js
index f63ee682f..1f15507d0 100644
--- a/js/id/renderer/map.js
+++ b/js/id/renderer/map.js
@@ -75,17 +75,19 @@ iD.Map = function() {
             filter = d3.functor(true);
         } else {
             var only = {};
-            difference.forEach(function buildDifference(id) {
+            for (var j = 0; j < difference.length; j++) {
+                var id = difference[j];
                 only[id] = graph.fetch(id);
                 if (only[id] && only[id].type === 'node') {
-                    graph.parentWays(id).forEach(function buildOnly(parent) {
+                    var parents = graph.parentWays(id);
+                    for (var k = 0; k < parents.length; k++) {
                         // Don't re-fetch parents
-                        if (only[parent.id] === undefined) {
-                            only[parent.id] = graph.fetch(parent.id);
+                        if (only[parents[k].id] === undefined) {
+                            only[parent.id] = graph.fetch(parents[k].id);
                         }
-                    });
+                    }
                 }
-            });
+            }
             all = _.compact(_.values(only));
             filter = function(d) { return d.accuracy ? d.way in only : d.id in only; };
         }