From 503219eb470ce0339a53572fb6e5f920591f77d7 Mon Sep 17 00:00:00 2001
From: Jakka Prihatna <jprihatna@gmail.com>
Date: Tue, 15 Sep 2020 09:23:02 +0700
Subject: [PATCH] [bugfix] allow calendar with falsy input (#5647)

---
 src/lib/moment/calendar.js  |  5 ++++-
 src/test/moment/calendar.js | 28 ++++++++++++++++++++++++++++
 2 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/src/lib/moment/calendar.js b/src/lib/moment/calendar.js
index 5d2998fac..fdd53dcb3 100644
--- a/src/lib/moment/calendar.js
+++ b/src/lib/moment/calendar.js
@@ -25,7 +25,10 @@ export function getCalendarFormat(myMoment, now) {
 export function calendar(time, formats) {
     // Support for single parameter, formats only overload to the calendar function
     if (arguments.length === 1) {
-        if (isMomentInput(arguments[0])) {
+        if (!arguments[0]) {
+            time = undefined;
+            formats = undefined;
+        } else if (isMomentInput(arguments[0])) {
             time = arguments[0];
             formats = undefined;
         } else if (isCalendarSpec(arguments[0])) {
diff --git a/src/test/moment/calendar.js b/src/test/moment/calendar.js
index 47ee29d7d..b1e472879 100644
--- a/src/test/moment/calendar.js
+++ b/src/test/moment/calendar.js
@@ -184,3 +184,31 @@ test('calendar overload format - passing one parameter - object w/ sameDay as fu
         'should equate'
     );
 });
+
+test('defaulting to current date', function (assert) {
+    var a = moment().hours(13).minutes(23).seconds(45);
+    assert.equal(moment(a).calendar(), 'Today at 1:23 PM', 'should equate');
+});
+
+test('calendar overload time - passing one parameter - a falsy value', function (assert) {
+    var a = moment().hours(13).minutes(23).seconds(45),
+        tests = [
+            '',
+            0,
+            -0,
+            // 0n,
+            false,
+            NaN,
+            null,
+            undefined,
+        ],
+        i;
+
+    for (i = 0; i < tests.length; ++i) {
+        assert.equal(
+            moment(a).calendar(tests[i]),
+            'Today at 1:23 PM',
+            'should equate'
+        );
+    }
+});
-- 
2.47.2