Support merging points into an area (#435)

index.html

@@ -83,6 +83,7 @@
         <script src="js/id/actions/delete_way.js"></script>
         <script src='js/id/actions/disconnect.js'></script>
         <script src='js/id/actions/join.js'></script>
+        <script src='js/id/actions/merge.js'></script>
         <script src='js/id/actions/move_node.js'></script>
         <script src='js/id/actions/move_way.js'></script>
         <script src='js/id/actions/circularize.js'></script>

js/id/actions/merge.js

@@ -0,0 +1,35 @@
+iD.actions.Merge = function(ids) {
+    function groupEntitiesByGeometry(graph) {
+        var entities = ids.map(function(id) { return graph.entity(id); });
+        return _.extend({point: [], area: []}, _.groupBy(entities, function(entity) { return entity.geometry(graph); }));
+    }
+
+    var action = function(graph) {
+        var geometries = groupEntitiesByGeometry(graph),
+            area = geometries['area'][0],
+            points = geometries['point'];
+
+        points.forEach(function (point) {
+            area = area.mergeTags(point.tags);
+
+            graph.parentRelations(point).forEach(function (parent) {
+                graph = graph.replace(parent.replaceMember(point, area));
+            });
+
+            graph = graph.remove(point);
+        });
+
+        graph = graph.replace(area);
+
+        return graph;
+    };
+
+    action.enabled = function(graph) {
+        var geometries = groupEntitiesByGeometry(graph);
+        return geometries['area'].length === 1 &&
+            geometries['point'].length > 0 &&
+            (geometries['area'].length + geometries['point'].length) === ids.length;
+    };
+
+    return action;
+};

js/id/operations/merge.js

@@ -1,18 +1,28 @@
 iD.operations.Merge = function(selection, context) {
-    var action = iD.actions.Join(selection);
+    var join = iD.actions.Join(selection),
+        merge = iD.actions.Merge(selection);
 
     var operation = function() {
         var annotation = t('operations.merge.annotation', {n: selection.length}),
-            difference = context.perform(action, annotation);
+            action;
+
+        if (join.enabled(context.graph())) {
+            action = join;
+        } else {
+            action = merge;
+        }
+
+        var difference = context.perform(action, annotation);
         context.enter(iD.modes.Select(context, difference.extantIDs()));
     };
 
     operation.available = function() {
-        return selection.length > 1;
+        return selection.length >= 2;
     };
 
     operation.enabled = function() {
-        return action.enabled(context.graph());
+        return join.enabled(context.graph()) ||
+            merge.enabled(context.graph());
     };
 
     operation.id = "merge";

test/index.html

@@ -80,6 +80,7 @@
     <script src="../js/id/actions/delete_way.js"></script>
     <script src='../js/id/actions/disconnect.js'></script>
     <script src='../js/id/actions/join.js'></script>
+    <script src='../js/id/actions/merge.js'></script>
     <script src='../js/id/actions/move_node.js'></script>
     <script src='../js/id/actions/move_way.js'></script>
     <script src='../js/id/actions/noop.js'></script>
@@ -157,6 +158,7 @@
     <script src="spec/actions/delete_way.js"></script>
     <script src='spec/actions/disconnect.js'></script>
     <script src="spec/actions/join.js"></script>
+    <script src='spec/actions/merge.js'></script>
     <script src="spec/actions/move_node.js"></script>
     <script src="spec/actions/move_way.js"></script>
     <script src="spec/actions/noop.js"></script>

test/index_packaged.html

@@ -42,6 +42,7 @@
     <script src="spec/actions/delete_way.js"></script>
     <script src='spec/actions/disconnect.js'></script>
     <script src="spec/actions/join.js"></script>
+    <script src='spec/actions/merge.js'></script>
     <script src="spec/actions/move_node.js"></script>
     <script src="spec/actions/move_way.js"></script>
     <script src="spec/actions/noop.js"></script>

test/spec/actions/merge.js

@@ -0,0 +1,20 @@
+describe("iD.actions.Merge", function () {
+    it("merges multiple points to an area", function () {
+        var graph = iD.Graph({
+                'a': iD.Node({id: 'a', tags: {a: 'a'}}),
+                'b': iD.Node({id: 'b', tags: {b: 'b'}}),
+                'w': iD.Way({id: 'w', tags: {area: 'yes'}}),
+                'r': iD.Relation({id: 'r', members: [{id: 'a', role: 'r', type: 'node'}]})
+            }),
+            action = iD.actions.Merge(['a', 'b', 'w']);
+
+        expect(action.enabled(graph)).to.be.true;
+
+        graph = action(graph);
+
+        expect(graph.entity('a')).to.be.undefined;
+        expect(graph.entity('b')).to.be.undefined;
+        expect(graph.entity('w').tags).to.eql({a: 'a', b: 'b', area: 'yes'});
+        expect(graph.entity('r').members).to.eql([{id: 'w', role: 'r', type: 'way'}]);
+    });
+});