Add iD.{Node,Way,Relation} constructors

Even if we don't want subclasses, they are handy for
assigning the right type and an appropriate ID.

js/iD/actions/modes.js

@@ -6,13 +6,10 @@ iD.modes = {};
 // into actions.
 
 iD.modes._node = function(ll) {
-    return iD.Entity({
-        type: 'node',
+    return iD.Node({
         lat: ll[1],
         lon: ll[0],
-        id: iD.Util.id('node'),
-        tags: {}
-    }, {});
+    });
 };
 
 iD.modes.AddPlace = {
@@ -57,16 +54,8 @@ iD.modes.AddPlace = {
 
 iD.modes.AddRoad = {
     title: "+ Road",
-    way: function(ll) {
-        return iD.Entity({
-            type: 'way',
-            nodes: [],
-            tags: {
-                highway: 'residential'
-            },
-            _updated: true,
-            id: iD.Util.id('way')
-        });
+    way: function() {
+        return iD.Way({tags: {highway: 'residential'}});
     },
     enter: function() {
         var surface = this.map.surface;
@@ -177,16 +166,8 @@ iD.modes.DrawRoad = function(way) {
 
 iD.modes.AddArea = {
     title: "+ Area",
-    way: function(ll) {
-        return iD.Entity({
-            type: 'way',
-            nodes: [],
-            tags: {
-                building: 'yes'
-            },
-            _updated: true,
-            id: iD.Util.id('way')
-        });
+    way: function() {
+        return iD.Way({tags: {building: 'yes'}});
     },
     enter: function() {
         var surface = this.map.surface;

js/iD/graph/Entity.js

@@ -7,6 +7,11 @@ iD.Entity = function(a, b) {
         this._updated = true;
     }
 
+    if (!this.id) {
+        this.id = iD.Util.id(this.type);
+        this._updated = true;
+    }
+
     if (iD.debug) {
         Object.freeze(this);
         Object.freeze(this.tags);
@@ -26,3 +31,15 @@ iD.Entity.prototype = {
         return this._updated && +this.id.slice(1) > 0;
     }
 };
+
+iD.Node = function (attrs) {
+    return iD.Entity(_.extend({}, attrs, {type: 'node'}));
+};
+
+iD.Way = function (attrs) {
+    return iD.Entity(_.extend({}, attrs, {type: 'way'}));
+};
+
+iD.Relation = function (attrs) {
+    return iD.Entity(_.extend({}, attrs, {type: 'relation'}));
+};

js/iD/graph/Way.js

@@ -7,8 +7,6 @@
 // If a a way is _closed_, it is assumed to be an area unless it has a
 // `highway` or `barrier` tag and is not also tagged `area`.
 
-iD.Way = {
-    isClosed: function(w) {
-        return (!w.nodes.length) || w.nodes[w.nodes.length - 1].id === w.nodes[0].id;
-    }
-};
+iD.Way.isClosed = function(w) {
+    return (!w.nodes.length) || w.nodes[w.nodes.length - 1].id === w.nodes[0].id;
+}

test/spec/Entity.js

@@ -16,7 +16,7 @@ describe('Entity', function () {
 
     describe("#created", function () {
         it("returns false for an unmodified Entity", function () {
-            expect(iD.Entity().created()).toBeFalsy();
+            expect(iD.Entity({id: 'w1234'}).created()).toBeFalsy();
         });
 
         it("returns false for a modified Entity with positive ID", function () {
@@ -30,7 +30,7 @@ describe('Entity', function () {
 
     describe("#modified", function () {
         it("returns false for an unmodified Entity", function () {
-            expect(iD.Entity().modified()).toBeFalsy();
+            expect(iD.Entity({id: 'w1234'}).modified()).toBeFalsy();
         });
 
         it("returns true for a modified Entity with positive ID", function () {
@@ -42,3 +42,21 @@ describe('Entity', function () {
         });
     });
 });
+
+describe('Node', function () {
+    it("returns a created Entity if no ID is specified", function () {
+        expect(iD.Node().created()).toBeTruthy();
+    });
+});
+
+describe('Way', function () {
+    it("returns a created Entity if no ID is specified", function () {
+        expect(iD.Way().created()).toBeTruthy();
+    });
+});
+
+describe('Relation', function () {
+    it("returns a created Entity if no ID is specified", function () {
+        expect(iD.Relation().created()).toBeTruthy();
+    });
+});