Add some utility methods to Way

js/id/graph/way.js

@@ -14,12 +14,24 @@ iD.Way = iD.Entity.extend({
         });
     },
 
+    first: function() {
+        return this.nodes[0];
+    },
+
+    last: function() {
+        return this.nodes[this.nodes.length - 1];
+    },
+
+    contains: function(node) {
+        return this.nodes.indexOf(node) >= 0;
+    },
+
     isOneWay: function() {
         return this.tags.oneway === 'yes';
     },
 
     isClosed: function() {
-        return this.nodes.length > 0 && this.nodes[this.nodes.length - 1] === this.nodes[0];
+        return this.nodes.length > 0 && this.first() === this.last();
     },
 
     // a way is an area if:

js/id/modes/draw_area.js

@@ -13,7 +13,7 @@ iD.modes.DrawArea = function(wayId) {
             headId = (way.nodes.length == 1) ?
                 way.nodes[0] :
                 way.nodes[way.nodes.length - 2],
-            tailId = _.first(way.nodes),
+            tailId = way.first(),
             node = iD.Node({loc: map.mouseCoordinates()});
 
         map.dblclickEnable(false)

js/id/modes/draw_line.js

@@ -12,8 +12,8 @@ iD.modes.DrawLine = function(wayId, direction) {
             way = history.graph().entity(wayId),
             node = iD.Node({loc: map.mouseCoordinates()}),
             index = (direction === 'forward') ? undefined : 0,
-            headId = (direction === 'forward') ? _.last(way.nodes) : _.first(way.nodes),
-            tailId = (direction === 'forward') ? _.first(way.nodes) : _.last(way.nodes);
+            headId = (direction === 'forward') ? way.last() : way.first(),
+            tailId = (direction === 'forward') ? way.first() : way.last();
 
         iD.behavior.Hover()(surface);
 

test/spec/graph/way.js

@@ -35,6 +35,28 @@ describe('iD.Way', function() {
         expect(iD.Way({tags: {foo: 'bar'}}).tags).to.eql({foo: 'bar'});
     });
 
+    describe("#first", function () {
+        it("returns the first node", function () {
+            expect(iD.Way({nodes: ['a', 'b', 'c']}).first()).to.equal('a');
+        });
+    });
+
+    describe("#last", function () {
+        it("returns the last node", function () {
+            expect(iD.Way({nodes: ['a', 'b', 'c']}).last()).to.equal('c');
+        });
+    });
+
+    describe("#contains", function () {
+        it("returns true if the way contains the given node", function () {
+            expect(iD.Way({nodes: ['a', 'b', 'c']}).contains('b')).to.be.true;
+        });
+
+        it("returns false if the way does not contain the given node", function () {
+            expect(iD.Way({nodes: ['a', 'b', 'c']}).contains('d')).to.be.false;
+        });
+    });
+
     describe("#extent", function () {
         it("returns the minimal extent containing all member nodes", function () {
             var node1 = iD.Node({loc: [0, 0]}),