JSON parser: more modern code style

Author: mmd-osm

leaflet-osm.js

@@ -322,7 +322,6 @@ L.OSM.XMLParser = {
   },
 
   getTags: function (xml) {
-
     var result = {};
 
     var tags = xml.getElementsByTagName("tag");
@@ -335,98 +334,61 @@ L.OSM.XMLParser = {
 }
 
 L.OSM.JSONParser = {
-  getChangesets: function (json) {
-    var result = [];
-
-    var changesets = json.changeset ? [json.changeset] : [];
-
-    for (var i = 0; i < changesets.length; i++) {
-      var cs = changesets[i];
-      result.push({
-        id: cs["id"].toString(),
-        type: "changeset",
-        latLngBounds: L.latLngBounds(
-          [cs["min_lat"], cs["min_lon"]],
-          [cs["max_lat"], cs["max_lon"]]),
-        tags: this.getTags(cs)
-      });
-    }
-
-    return result;
+  getChangesets(json) {
+    const changesets = json.changeset ? [json.changeset] : [];
+
+    return changesets.map(cs => ({
+      id: String(cs.id),
+      type: "changeset",
+      latLngBounds: L.latLngBounds(
+        [cs.min_lat, cs.min_lon],
+        [cs.max_lat, cs.max_lon]
+      ),
+      tags: this.getTags(cs)
+    }));
   },
 
-  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"];
+  getNodes(json) {
+    const nodes = json.elements?.filter(el => el.type === "node") ?? [];
+    let result = {};
 
-      result[id] = {
-        id: id.toString(),
+    for (const node of nodes) {
+      result[node.id] = {
+        id: String(node.id),
         type: "node",
-        latLng: L.latLng(node["lat"],
-                         node["lon"],
-                         true),
+        latLng: L.latLng(node.lat, node.lon, true),
         tags: this.getTags(node)
       };
     }
 
     return result;
   },
 
-  getWays: function (json, nodes) {
-    var result = [];
+  getWays(json, nodes) {
+    const ways = json.elements?.filter(el => el.type === "way") ?? [];
 
-    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"].toString(),
-        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;
+    return ways.map(way => ({
+      id: String(way.id),
+      type: "way",
+      nodes: way.nodes.map(nodeId => nodes[nodeId]),
+      tags: this.getTags(way)
+    }));
   },
 
-  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"].toString(),
-        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;
+  getRelations(json, nodes) {
+    const relations = json.elements?.filter(el => el.type === "relation") ?? [];
+
+    return relations.map(rel => ({
+      id: String(rel.id),
+      type: "relation",
+      members: (rel.members ?? [])   // relation-way and relation-relation membership not implemented
+        .map(member => member.type === "node" ? nodes[member.ref] : null)
+        .filter(Boolean),     // filter out null and undefined
+      tags: this.getTags(rel)
+    }));
   },
 
-  getTags: function (json) {
-    return json["tags"];
+  getTags(json) {
+    return json.tags ?? {};
   }
-}
+};