Entity as a mixin rather than a sub-object.

NOTES.md

@@ -1,3 +1,16 @@
+## The Graph
+
+iD implements a [persistent data structure](http://en.wikipedia.org/wiki/Persistent_data_structure)
+over the OSM data model.
+
+To be clear, this data model is something like
+
+
+    root -> relations (-> relations) -> ways -> nodes
+       \                             \> nodes
+        \-  ways -> nodes
+         \- nodes
+
 ## Actions
 
 Actions are operations on OSM data like adding nodes, moving ways,

index.html

@@ -31,10 +31,10 @@
         <script type="text/javascript" src="js/iD/renderer/markers.js"></script>
         <script type="text/javascript" src="js/iD/ui/Inspector.js"></script>
 
+        <script type="text/javascript" src="js/iD/Entity.js"></script>
         <script type="text/javascript" src="js/iD/GeoJSON.js"></script>
         <script type="text/javascript" src="js/iD/Node.js"></script>
         <script type="text/javascript" src="js/iD/Relation.js"></script>
-        <script type="text/javascript" src="js/iD/Entity.js"></script>
         <script type="text/javascript" src="js/iD/Way.js"></script>
         <script type="text/javascript" src="js/iD/Connection.js"></script>
         <script type="text/javascript" src="js/iD/Graph.js"></script>

js/iD/Entity.js

@@ -1,14 +1,7 @@
-iD.Entity = function () {
-    this.parents = {};
-    this._id = iD.Util.id();
-    this.id = NaN;
-    this.loaded = false;
-    this.type = '';
-    this.modified = false;
-    this.deleted = false;
-};
+iD.Entity = function () { };
 
 iD.Entity.prototype = {
+    parents: {},
     // a relation or way which contains this entity
     addParent: function (x) {
         this.parents[x._id] = x;

js/iD/Node.js

@@ -2,7 +2,6 @@ iD.Node = function(id, lat, lon, tags, loaded) {
 	this.type = 'node';
 	this.id = id;
 	this._id = iD.Util.id();
-	this.entity = new iD.Entity();
 	this.lat = lat;
 	this.lon = lon;
 	this[0] = lon;
@@ -19,3 +18,5 @@ iD.Node.prototype = {
             (this.lat >= extent[1][1]);
     }
 };
+
+iD.Util.extend(iD.Node, iD.Entity);

js/iD/Relation.js

@@ -1,11 +1,11 @@
-iD.Relation = function(id, members, tags, loaded) {
+iD.Relation = function(id, children, tags, loaded) {
     members = members || [];
     tags = tags || {};
     this.type = 'relation';
     this.id = id;
     this._id = iD.Util.id();
 	this.entity = new iD.Entity();
-    this.members = members;
+    this.children = children;
     this.tags = tags;
     this.modified = this.id < 0;
     this.loaded = (loaded === undefined) ? true : loaded;
@@ -15,6 +15,8 @@ iD.Relation.prototype = {
     intersects: function() { return true; }
 };
 
+iD.Util.extend(iD.Relation, iD.Entity);
+
 iD.RelationMember = function(entity, role) {
     this.entity = entity;
     this.role = role;

js/iD/Util.js

@@ -30,3 +30,11 @@ iD.Util.friendlyName = function(entity) {
     return n.length === 0 ? 'unknown' : n.join('; ');
 };
 
+iD.Util.extend = function(child, parent) {
+    for (var property in parent.prototype) {
+        if (typeof child.prototype[property] == "undefined") {
+            child.prototype[property] = parent.prototype[property];
+        }
+    }
+    return child;
+};

js/iD/Way.js

@@ -12,27 +12,19 @@ iD.Way = function(id, nodes, tags, loaded) {
     this.type = 'way';
     this.id = id;
     this._id = iD.Util.id();
-    this.deleted = false;
-    this.entity = new iD.Entity();
     this.tags = tags;
-    this.nodes = nodes;
+    this.children = nodes;
     this.loaded = (loaded === undefined) ? true : loaded;
     this.extent = {};
 };
 
 iD.Way.prototype = {
 
-    addNode: function(node) {
-        this.nodes.push(node);
-        this._bounds = null;
-        return this;
-    },
-
     // JOSM: http://josm.openstreetmap.de/browser/josm/trunk/src/org/openstreetmap/josm/data/osm/Way.java#L466
     isClosed: function() {
         // summary:	Is this a closed way (first and last nodes the same)?
-        if (!this.nodes.length) return true;
-        return this.nodes[this.nodes.length - 1] === this.nodes[0];
+        if (!this.children.length) return true;
+        return this.children[this.children.length - 1] === this.children[0];
     },
 
     isType: function(type) {
@@ -56,9 +48,10 @@ iD.Way.prototype = {
     // ---------------------
     // Bounding-box handling
     intersects: function(extent) {
+        // TODO: rewrite with new id-mapping
         return true;
         // No-node ways are inside of nothing.
-        if (!this.nodes.length) return false;
+        if (!this.children.length) return false;
         var bounds = this.bounds();
         // left
         return !(
@@ -72,3 +65,5 @@ iD.Way.prototype = {
             bounds[0][1] > extent[1][1]);
     }
 };
+
+iD.Util.extend(iD.Way, iD.Entity);

js/iD/renderer/Map.js

@@ -113,7 +113,7 @@ iD.Map = function(obj) {
     }
 
     function nodeline(d) {
-        return linegen(d.nodes.map(function(n) {
+        return linegen(d.children.map(function(n) {
             return connection.graph().index[n];
         }));
     }
@@ -163,7 +163,7 @@ iD.Map = function(obj) {
         });
 
         var handles = layers[0].hit.selectAll('circle.handle')
-            .data(active_entity.length ? active_entity[0].nodes : [], key);
+            .data(active_entity.length ? active_entity[0].children : [], key);
 
         handles.exit().remove();
         fills.exit().remove();

test/index.html

@@ -13,16 +13,15 @@
   <script type="text/javascript" src="../js/lib/underscore-min.js"></script>
   <script type="text/javascript" src="../js/lib/d3.v2.min.js"></script>
   <script type="text/javascript" src="../js/iD/id.js"></script>
+  <script type="text/javascript" src="../js/iD/Entity.js"></script>
   <script type="text/javascript" src="../js/iD/Util.js"></script>
   <script type="text/javascript" src="../js/iD/Node.js"></script>
   <script type="text/javascript" src="../js/iD/Relation.js"></script>
-  <script type="text/javascript" src="../js/iD/Entity.js"></script>
   <script type="text/javascript" src="../js/iD/GeoJSON.js"></script>
   <script type="text/javascript" src="../js/iD/Way.js"></script>
   <script type="text/javascript" src="../js/iD/Connection.js"></script>
   <script type="text/javascript" src="../js/iD/actions/UndoStack.js"></script>
   <script type="text/javascript" src="../js/iD/ui/Inspector.js"></script>
-  <script type="text/javascript" src="../js/iD/Controller.js"></script>
   <script type="text/javascript" src="../js/iD/renderer/markers.js"></script>
   <script type="text/javascript" src="../js/iD/renderer/Map.js"></script>
   <script type="text/javascript" src="../js/iD/renderer/Style.js"></script>

test/spec/Entity.js

@@ -5,10 +5,6 @@ describe('Entity', function () {
         entity = new iD.Entity();
     });
 
-    it('has no entity type', function () {
-        expect(entity.type).toEqual('');
-    });
-
     describe('#parentWays', function () {
         it('returns an array of parents with entityType way', function () {
             entity.addParent({_id: 1, type: 'way'});

test/spec/Way.js

@@ -11,7 +11,7 @@ describe('Way', function() {
   });
 
   it('has zero nodes by default', function() {
-      expect(way.nodes.length).toEqual(0);
+      expect(way.children.length).toEqual(0);
   });
 
   describe('#isClosed', function() {