feat(name): use "name:en" as a fallback for when no default name was …

…found

stream/tag_mapper.js

@@ -67,6 +67,15 @@ module.exports = function(){
         }
       }
 
+      // Handle the case where no default name was set but there was
+      // an english name which we could use as the default.
+      if( !doc.getName('default') ){
+        var en = doc.getName('en');
+        if( 'string' === typeof en ){
+          doc.setName('default', en);
+        }
+      }
+
       // Import airport codes as aliases
       if( tags.hasOwnProperty('aerodrome') || tags.hasOwnProperty('aeroway') ){
         if( tags.hasOwnProperty('iata') ){

test/stream/tag_mapper.js

@@ -156,6 +156,25 @@ module.exports.tests.accept_localized_keys = function(test, common) {
   });
 };
 
+// Use 'name:en' in situations where no other default name was available
+// https://github.com/pelias/openstreetmap/issues/497
+module.exports.tests.use_en_as_fallback_default = function (test, common) {
+  var doc = new Document('a', 'b', 1);
+  doc.setMeta('tags', { 'name:ru': 'test1', 'name:pl': 'test2', 'name:en': 'test3' });
+  test('maps - use name:en as fallback default', function (t) {
+    var stream = mapper();
+    stream.pipe(through.obj(function (doc, enc, next) {
+      t.equal(doc.getName('default'), 'test3', 'name:en used as fallback');
+      t.equal(doc.getName('ru'), 'test1', 'correctly mapped');
+      t.equal(doc.getName('pl'), 'test2', 'correctly mapped');
+      t.equal(doc.getName('en'), 'test3', 'correctly mapped');
+      t.end(); // test will fail if not called (or called twice).
+      next();
+    }));
+    stream.write(doc);
+  });
+};
+
 module.exports.tests.lowercase_keys = function(test, common) {
   var doc = new Document('a','b',1);
   doc.setMeta('tags', { 'name:EN': 'test' });