Add support for OSM JSON format

Author: mmd-osm

leaflet-osm.js

@@ -141,11 +141,14 @@ L.OSM.DataLayer = L.FeatureGroup.extend({
     }
   },
 
-  buildFeatures: function (xml) {
-    var features = L.OSM.getChangesets(xml),
-      nodes = L.OSM.getNodes(xml),
-      ways = L.OSM.getWays(xml, nodes),
-      relations = L.OSM.getRelations(xml, nodes, ways);
+  buildFeatures: function (data, format = "application/xml") {
+
+    const parser = (format === "application/json") ? L.OSM.JSONParser : L.OSM.XMLParser;
+
+    var features = parser.getChangesets(data),
+        nodes = parser.getNodes(data),
+        ways = parser.getWays(data, nodes),
+        relations = parser.getRelations(data, nodes, ways);
 
     var wayNodes = {}
     for (var i = 0; i < ways.length; i++) {
@@ -228,7 +231,7 @@ L.OSM.DataLayer = L.FeatureGroup.extend({
   },
 });
 
-L.Util.extend(L.OSM, {
+L.OSM.XMLParser = {
   getChangesets: function (xml) {
     var result = [];
 
@@ -328,4 +331,100 @@ L.Util.extend(L.OSM, {
 
     return result;
   }
-});
+}
+
+L.OSM.JSONParser = {
+  getChangesets: function (json) {
+    var result = [];
+
+    var nodes = json.elements.filter(d => d.type === "changeset");
+    for (var i = 0; i < nodes.length; i++) {
+      var node = nodes[i], id = node["id"];
+      result.push({
+        id: id,
+        type: "changeset",
+        latLngBounds: L.latLngBounds(
+          [node["min_lat"], node["min_lon"]],
+          [node["max_lat"], node["max_lon"]]),
+        tags: this.getTags(node)
+      });
+    }
+
+    return result;
+  },
+
+  getNodes: function (json) {
+    var result = {};
+
+    var nodes = json.elements.filter(d => d.type === "node");
+    for (var i = 0; i < nodes.length; i++) {
+      var node = nodes[i], id = node["id"];
+
+      result[id] = {
+        id: id,
+        type: "node",
+        latLng: L.latLng(node["lat"],
+                         node["lon"],
+                         true),
+        tags: this.getTags(node)
+      };
+    }
+
+    return result;
+  },
+
+  getWays: function (json, nodes) {
+    var result = [];
+
+    var ways = json.elements.filter(d => d.type === "way");
+    for (var i = 0; i < ways.length; i++) {
+      var way = ways[i], nds = way.nodes;
+
+      var way_object = {
+        id: way["id"],
+        type: "way",
+        nodes: new Array(nds.length),
+        tags: this.getTags(way)
+      };
+
+      for (var j = 0; j < nds.length; j++) {
+         way_object.nodes[j] = nodes[nds[j]];
+      }
+
+      result.push(way_object);
+    }
+
+    return result;
+  },
+
+  getRelations: function (json, nodes, ways) {
+    var result = [];
+
+    var rels = json.elements.filter(d => d.type === "relation");
+    for (var i = 0; i < rels.length; i++) {
+      var rel = rels[i], members = rel["members"];
+
+      var rel_object = {
+        id: rel["id"],
+        type: "relation",
+        members: new Array(members.length),
+        tags: this.getTags(rel)
+      };
+
+      for (var j = 0; j < members.length; j++) {
+        if (members[j]["type"] === "node")
+          rel_object.members[j] = nodes[members[j]["ref"]];
+        else // relation-way and relation-relation membership not implemented
+          rel_object.members[j] = null;
+      }
+      rel_object.members = rel_object.members.filter(i => i !== null && i !== undefined)
+      result.push(rel_object);
+    }
+
+    return result;
+  },
+
+  getTags: function (json) {
+    return json["tags"];
+  }
+}