Use existing nodes where possible in almost junction connection fix

modules/actions/merge_nodes.js

@@ -7,7 +7,7 @@ import { geoVecAdd, geoVecScale } from '../geo';
 // 1. move all the nodes to a common location
 // 2. `actionConnect` them
 
-export function actionMergeNodes(nodeIDs) {
+export function actionMergeNodes(nodeIDs, loc) {
 
     // If there is a single "interesting" node, use that as the location.
     // Otherwise return the average location of all the nodes.
@@ -31,11 +31,16 @@ export function actionMergeNodes(nodeIDs) {
 
     var action = function(graph) {
         if (nodeIDs.length < 2) return graph;
-        var toLoc = chooseLoc(graph);
+        var toLoc = loc;
+        if (!toLoc) {
+            toLoc = chooseLoc(graph);
+        }
 
         for (var i = 0; i < nodeIDs.length; i++) {
             var node = graph.entity(nodeIDs[i]);
-            graph = graph.replace(node.move(toLoc));
+            if (node.loc !== toLoc) {
+                graph = graph.replace(node.move(toLoc));
+            }
         }
 
         return actionConnect(nodeIDs)(graph);

modules/geo/geo.js

@@ -66,3 +66,23 @@ export function geoZoomToScale(z, tileSize) {
     return tileSize * Math.pow(2, z) / TAU;
 }
 
+
+// returns info about the node from `nodes` closest to the given `point`
+export function geoSphericalClosestNode(nodes, point) {
+    var minDistance = Infinity, distance;
+    var indexOfMin;
+
+    for (var i in nodes) {
+        distance = geoSphericalDistance(nodes[i].loc, point);
+        if (distance < minDistance) {
+            minDistance = distance;
+            indexOfMin = i;
+        }
+    }
+
+    if (indexOfMin !== undefined) {
+        return { index: indexOfMin, distance: minDistance, node: nodes[indexOfMin] };
+    } else {
+        return null;
+    }
+}

modules/geo/index.js

@@ -7,6 +7,7 @@ export { geoMetersToLon } from './geo.js';
 export { geoMetersToOffset } from './geo.js';
 export { geoOffsetToMeters } from './geo.js';
 export { geoScaleToZoom } from './geo.js';
+export { geoSphericalClosestNode } from './geo.js';
 export { geoSphericalDistance } from './geo.js';
 export { geoZoomToScale } from './geo.js';
 

modules/validations/almost_junction.js

@@ -6,14 +6,16 @@ import {
     geoMetersToLon,
     geoSphericalDistance,
     geoVecInterp,
-    geoHasSelfIntersections
+    geoHasSelfIntersections,
+    geoSphericalClosestNode
 } from '../geo';
 import {
     utilDisplayLabel
 } from '../util';
 import {
     actionAddMidpoint,
-    actionChangeTags
+    actionChangeTags,
+    actionMergeNodes
 } from '../actions';
 import { t } from '../util/locale';
 import {
@@ -135,20 +137,30 @@ export function validationAlmostJunction() {
         extendableNodeInfos.forEach(function(extendableNodeInfo) {
             var node = extendableNodeInfo.node;
             var edgeHighway = graph.entity(extendableNodeInfo.wid);
-            var fixes = [
-              new validationIssueFix({
-                  title: t('issues.fix.connect_almost_junction.title'),
-                  onClick: function() {
-                      var endNode = this.issue.entities[1],
-                          targetEdge = this.issue.info.edge,
-                          crossLoc = this.issue.info.cross_loc;
-                      context.perform(
-                          actionAddMidpoint({loc: crossLoc, edge: targetEdge}, endNode),
-                          t('issues.fix.connect_almost_junction.undo_redo')
-                      );
-                  }
-              })
-            ];
+            var fixes = [new validationIssueFix({
+                title: t('issues.fix.connect_almost_junction.title'),
+                onClick: function() {
+                    var endNode = this.issue.entities[1],
+                        edgeWay = this.issue.entities[2],
+                        crossLoc = this.issue.info.cross_loc;
+                    var edgeWayNodes = context.graph().childNodes(edgeWay);
+                    var closestNodeInfo = geoSphericalClosestNode(edgeWayNodes, crossLoc);
+                    // if there is already a point nearby, just connect to that
+                    if (closestNodeInfo.distance < 0.8) {
+                        context.perform(
+                            actionMergeNodes([closestNodeInfo.node.id, endNode.id], closestNodeInfo.node.loc),
+                            t('issues.fix.connect_almost_junction.undo_redo')
+                        );
+                    // else add the end node to the edge way
+                    } else {
+                        var targetEdge = this.issue.info.edge;
+                        context.perform(
+                            actionAddMidpoint({loc: crossLoc, edge: targetEdge}, endNode),
+                            t('issues.fix.connect_almost_junction.undo_redo')
+                        );
+                    }
+                }
+            })];
             if (Object.keys(node.tags).length === 0) {
                 // node has no tags, suggest noexit fix
                 fixes.push(new validationIssueFix({