message view: Recipient bar date stamp shows older years.

timerender.js render_now() will always include older
years when rendering the date stamp on the recipient bar
and the date rows above messages.

Fixes #4843.

frontend_tests/node_tests/timerender.js

@@ -64,6 +64,20 @@ var timerender = require('js/timerender.js');
     assert.equal(expected.needs_update, actual.needs_update);
 }());
 
+(function test_render_now_returns_year_with_year_boundary() {
+    var today = new XDate(1555091573000); // Friday 4/12/2019 5:52:53 PM (UTC+0)
+    var three_months_ago = today.clone().addMonths(-6, true);
+    var expected = {
+        time_str: 'Oct 12, 2018',
+        formal_time_str: 'Friday, October 12, 2018',
+        needs_update: false,
+    };
+    var actual = timerender.render_now(three_months_ago, today);
+    assert.equal(expected.time_str, actual.time_str);
+    assert.equal(expected.formal_time_str, actual.formal_time_str);
+    assert.equal(expected.needs_update, actual.needs_update);
+}());
+
 (function test_render_date_renders_time_html() {
     var today = new XDate(1555091573000); // Friday 4/12/2019 5:52:53 PM (UTC+0)
     var message_time  = today.clone();

static/js/timerender.js

@@ -35,15 +35,18 @@ exports.render_now = function (time, today) {
     // constants.
     var days_old = Math.round(start_of_other_day.diffDays(start_of_today));
 
+    var is_older_year =
+        (start_of_today.getFullYear() - start_of_other_day.getFullYear()) > 0;
+
     if (days_old === 0) {
         time_str = i18n.t("Today");
         needs_update = true;
     } else if (days_old === 1) {
         time_str = i18n.t("Yesterday");
         needs_update = true;
-    } else if (days_old >= 365) {
+    } else if (is_older_year) {
         // For long running servers, searching backlog can get ambiguous
-        // without a year stamp. Only show year if message is over a year old.
+        // without a year stamp. Only show year if message is from an older year
         time_str = time.toString("MMM\xa0dd,\xa0yyyy");
         needs_update = false;
     } else {