merge way nodes action is added

modules/actions/index.js

@@ -18,6 +18,7 @@ export { actionDiscardTags } from './discard_tags';
 export { actionDisconnect } from './disconnect';
 export { actionJoin } from './join';
 export { actionMerge } from './merge';
+export { actionMergeWayNodes } from './merge_way_nodes';
 export { actionMergePolygon } from './merge_polygon';
 export { actionMergeRemoteChanges } from './merge_remote_changes';
 export { actionMove } from './move';

modules/actions/merge_way_nodes.js

@@ -0,0 +1,55 @@
+import _sum from 'lodash-es/sum';
+
+import { osmNode } from '../osm/node';
+
+
+export function actionMergeWayNodes (ids) {
+    function getSelectedEntities (graph) {
+        return ids.map(function (id) { return graph.entity(id); });
+    }
+
+    function calcAverageLoc (nodes) {
+        return [
+            _sum(nodes.map(function (node) { return node.loc[0]; })) / nodes.length,
+            _sum(nodes.map(function (node) { return node.loc[1]; })) / nodes.length
+        ];
+    }
+
+    function replaceWithinWays (newNode) {
+        return function (graph, node) {
+            return graph.parentWays(node).reduce(function (graph, way) {
+                return graph.replace(way.replaceNode(node.id, newNode.id));
+            }, graph);
+        };
+    }
+
+    function removeFromGraph (graph, entity) {
+        return graph.remove(entity);
+    }
+
+    var action = function (graph) {
+        var nodes = getSelectedEntities(graph),
+            newNode = new osmNode({ loc: calcAverageLoc(nodes) });
+
+        graph = graph.replace(newNode);
+
+        graph = nodes.reduce(replaceWithinWays(newNode), graph);
+
+        graph = nodes.reduce(removeFromGraph, graph);
+
+        return graph;
+    };
+
+    action.disabled = function (graph) {
+        function isNotWayNode (entity) { return entity.type !== 'node' || graph.parentWays(entity) <= 0; }
+        function isNotExtremeNode (node) { return !node.isEndpoint(graph); }
+
+        var entities = getSelectedEntities(graph);
+
+        if (entities.some(isNotWayNode) || entities.some(isNotExtremeNode)) {
+            return 'not_eligible';
+        }
+    };
+
+    return action;
+}