make score always return a number as spec'd, #21886

src/vs/editor/common/modes/languageSelector.ts

@@ -91,7 +91,7 @@ export function score(selector: LanguageSelector, candidateUri: URI, candidateLa
 		}
 
 	} else {
-		return undefined;
+		return 0;
 	}
 }
 

src/vs/editor/test/common/modes/languageSelector.test.ts

@@ -18,8 +18,8 @@ suite('LanguageSelector', function () {
 
 	test('score, invalid selector', function () {
 		assert.equal(score({}, model.uri, model.language), 0);
-		assert.equal(score(undefined, model.uri, model.language), undefined);
-		assert.equal(score(null, model.uri, model.language), undefined);
+		assert.equal(score(undefined, model.uri, model.language), 0);
+		assert.equal(score(null, model.uri, model.language), 0);
 		assert.equal(score('', model.uri, model.language), 0);
 	});