From 89636736a454a24f0a073640205a20495969d982 Mon Sep 17 00:00:00 2001
From: harttle <yangjvn@126.com>
Date: Thu, 8 Dec 2016 23:25:38 +0800
Subject: [PATCH] robust date filter

---
 filters.js      | 2 +-
 test/filters.js | 3 +++
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/filters.js b/filters.js
index 0ed743611..3ea8e75b8 100644
--- a/filters.js
+++ b/filters.js
@@ -23,7 +23,7 @@ var filters = {
     'ceil': v => Math.ceil(v),
     'date': (v, arg) => {
         if (v === 'now') v = new Date();
-        return strftime(v, arg);
+        return v instanceof Date ? strftime(v, arg) : '';
     },
     'default': (v, arg) => v || arg,
     'divided_by': (v, arg) => Math.floor(v / arg),
diff --git a/test/filters.js b/test/filters.js
index 95033fd23..0aef8554b 100644
--- a/test/filters.js
+++ b/test/filters.js
@@ -51,6 +51,9 @@ describe('filters', function() {
         it('should create a new Date when given "now"', function() {
             return test('{{ "now" | date: "%Y"}}', (new Date).getFullYear().toString());
         });
+        it('should render as empty string when invalid', function() {
+            return test('{{ "" | date: "%Y"}}', "");
+        });
     });
 
     describe('default', function() {