iD.actions.Join

js/id/actions/join.js

@@ -0,0 +1,65 @@
+// Join ways at the end node they share.
+//
+// This is the inverse of `iD.actions.Split`.
+//
+// Reference:
+//   https://github.com/systemed/potlatch2/blob/master/net/systemeD/halcyon/connection/actions/MergeWaysAction.as
+//   https://github.com/openstreetmap/josm/blob/mirror/src/org/openstreetmap/josm/actions/CombineWayAction.java
+//
+iD.actions.Join = function(idA, idB) {
+    var action = function(graph) {
+        var a = graph.entity(idA),
+            b = graph.entity(idB),
+            nodes, tags;
+
+        if (a.first() === b.first()) {
+            // a <-- b ==> c
+            // Expected result:
+            // a <-- b <-- c
+            nodes = b.nodes.slice().reverse().concat(a.nodes.slice(1));
+
+        } else if (a.first() === b.last()) {
+            // a <-- b <== c
+            // Expected result:
+            // a <-- b <-- c
+            nodes = b.nodes.concat(a.nodes.slice(1));
+
+        } else if (a.last()  === b.first()) {
+            // a --> b ==> c
+            // Expected result:
+            // a --> b --> c
+            nodes = a.nodes.concat(b.nodes.slice(1));
+
+        } else if (a.last()  === b.last()) {
+            // a --> b <== c
+            // Expected result:
+            // a --> b --> c
+            nodes = a.nodes.concat(b.nodes.slice().reverse().slice(1));
+        }
+
+        graph.parentRelations(b)
+            .forEach(function (parent) {
+                var memberA = parent.memberById(idA),
+                    memberB = parent.memberById(idB);
+                if (!memberA) {
+                    graph = graph.replace(parent.addMember({id: idA, role: memberB.role}));
+                }
+            });
+
+        graph = graph.replace(a.mergeTags(b.tags).update({nodes: nodes}));
+        graph = iD.actions.DeleteWay(idB)(graph);
+
+        return graph;
+    };
+
+    action.enabled = function(graph) {
+        var a = graph.entity(idA),
+            b = graph.entity(idB);
+        return a.first() === b.first() ||
+               a.first() === b.last()  ||
+               a.last()  === b.first() ||
+               a.last()  === b.last();
+    };
+
+    return action;
+};

js/id/actions/split.js

@@ -1,5 +1,7 @@
 // Split a way at the given node.
 //
+// This is the inverse of `iD.actions.Join`.
+//
 // For testing convenience, accepts an ID to assign to the new way.
 // Normally, this will be undefined and the way will automatically
 // be assigned a new ID.