use "name:en" as a fallback for when no default name was found

stream/tag_mapper.js

@@ -67,6 +67,37 @@ module.exports = function(){
         }
       }
 
+      // Handle the case where no default name was set but there were
+      // other names which we could use as the default.
+      if( !doc.getName('default') ){
+
+        var defaultName =
+          doc.getName('official') ||
+          doc.getName('international') ||
+          doc.getName('national') ||
+          doc.getName('regional') ||
+          doc.getName('en');
+
+        // use one of the preferred name tags listed above
+        if ( defaultName ){
+          doc.setName('default', defaultName);
+        }
+
+        // else try to use an available two-letter language name tag
+        else {
+          var keys = Object.keys(doc.name).filter(n => n.length === 2);
+
+          // unambiguous (there is only a single two-letter name tag)
+          if ( keys.length === 1 ){
+            doc.setName('default', doc.getName(keys[0]));
+          }
+
+          // note we do not handle ambiguous cases where the record contains >1
+          // two-letter name tags.
+          // see: https://github.com/pelias/openstreetmap/pull/498
+        }
+      }
+
       // Import airport codes as aliases
       if( tags.hasOwnProperty('aerodrome') || tags.hasOwnProperty('aeroway') ){
         if( tags.hasOwnProperty('iata') ){

test/fixtures/combined_vancouver_queens.json

@@ -115938,6 +115938,37 @@
       "source_id": "node/2900172775"
     }
   },
+  {
+    "_index": "pelias",
+    "_type": "venue",
+    "_id": "node/2900172775",
+    "data": {
+      "name": {
+        "en": "Soka Gakkai International (SGI) Vancouver Culture Centre",
+        "default": "Soka Gakkai International (SGI) Vancouver Culture Centre"
+      },
+      "phrase": {
+        "en": "Soka Gakkai International (SGI) Vancouver Culture Centre",
+        "default": "Soka Gakkai International (SGI) Vancouver Culture Centre"
+      },
+      "address_parts": {
+        "number": "8401",
+        "zip": "V6P 3J9",
+        "street": "Cambie Street"
+      },
+      "center_point": {
+        "lon": -123.117345,
+        "lat": 49.209697
+      },
+      "category": [
+        "education",
+        "entertainment"
+      ],
+      "source": "openstreetmap",
+      "layer": "venue",
+      "source_id": "node/2900172775"
+    }
+  },
   {
     "_index": "pelias",
     "_type": "address",

test/stream/tag_mapper.js

@@ -156,6 +156,75 @@ module.exports.tests.accept_localized_keys = function(test, common) {
   });
 };
 
+// Use 'name:official' in situations where no other default name was available
+// https://github.com/pelias/openstreetmap/issues/497
+module.exports.tests.use_official_as_fallback_default = function (test, common) {
+  var doc = new Document('a', 'b', 1);
+  doc.setMeta('tags', { 'name:ru': 'test1', 'name:en': 'test2', 'official_name': 'test3' });
+  test('maps - use name:official 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('en'), 'test2', 'correctly mapped');
+      t.equal(doc.getName('official'), 'test3', 'correctly mapped');
+      t.end(); // test will fail if not called (or called twice).
+      next();
+    }));
+    stream.write(doc);
+  });
+};
+
+// 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);
+  });
+};
+
+// Use the *only* available name:** tag as fallback
+module.exports.tests.unambiguous_default_name_fallback = function (test, common) {
+  var doc = new Document('a', 'b', 1);
+  doc.setMeta('tags', { 'name:ru': 'test1' });
+  test('maps - unambiguous name:** used as default name fallback', function (t) {
+    var stream = mapper();
+    stream.pipe(through.obj(function (doc, enc, next) {
+      t.equal(doc.getName('default'), 'test1', 'only name:** tag used as fallback');
+      t.equal(doc.getName('ru'), 'test1', 'correctly mapped');
+      t.end(); // test will fail if not called (or called twice).
+      next();
+    }));
+    stream.write(doc);
+  });
+};
+
+// In cases where there are multiple name:** tags, do not try to guess
+module.exports.tests.ambiguous_default_name_fallback = function (test, common) {
+  var doc = new Document('a', 'b', 1);
+  doc.setMeta('tags', { 'name:ru': 'test1', 'name:pl': 'test2' });
+  test('maps - ambiguous name:** not used as default name fallback', function (t) {
+    var stream = mapper();
+    stream.pipe(through.obj(function (doc, enc, next) {
+      t.false(doc.getName('default'), 'do not try to guess');
+      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' });