Reimplement relative time formatting as a filter, dropping dependency on deprecated moment.js

Signed-off-by: Alec Kojaev <alec@kojaev.name>

1 files changed, 58 insertions, 0 deletions

diff --git a/js/filter/RelativeTimestamp.js b/js/filter/RelativeTimestamp.js
new file mode 100644
index 000000000..1a70db4a7
--- /dev/null
+++ b/js/filter/RelativeTimestamp.js
@@ -0,0 +1,58 @@
+/**
+ * Nextcloud - News
+ *
+ * This file is licensed under the Affero General Public License version 3 or
+ * later. See the COPYING file.
+ *
+ * @author Alec Kojaev <alec@kojaev.name>
+ * @copyright Alec Kojaev 2021
+ */
+app.filter('relativeTimestamp', ['SettingsResource', function (SettingsResource) {
+    'use strict';
+
+    const languageCode = SettingsResource.get('language');
+    const relFormat = Intl.RelativeTimeFormat ?
+        new Intl.RelativeTimeFormat(languageCode, { numeric: 'auto' }) : null;
+    const maxRelDistance = 90*86400*1000;
+    const relLimits = [
+        [ 7*86400*1000, 'week'   ],
+        [   86400*1000, 'day'    ],
+        [    3600*1000, 'hour'   ],
+        [      60*1000, 'minute' ],
+        [       1*1000, 'second' ]
+    ];
+    const absLimits = [
+        [ 7*86400*1000, { hour: '2-digit', minute: '2-digit', dayPeriod: 'narrow',
+                          year: 'numeric', month: 'short', day: 'numeric' } ],
+        [   43200*1000, { hour: '2-digit', minute: '2-digit', dayPeriod: 'narrow',
+                          weekday: 'long' } ],
+        [            0, { hour: '2-digit', minute: '2-digit', dayPeriod: 'narrow' } ]
+    ];
+
+    return function (timestamp) {
+        if (!Number.isFinite(timestamp)) {
+            return timestamp;
+        }
+        const ts = new Date(timestamp);
+        const dist = ts.getTime() - Date.now();
+        const absDist = Math.abs(dist);
+        if (relFormat && absDist < maxRelDistance) {
+            for (const [ scale, unit ] of relLimits) {
+                const value = Math.trunc(dist / scale);
+                if (value !== 0) {
+                    return relFormat.format(value, unit);
+                }
+            }
+            // We arrive here only if distance from now is less than 1 second
+            return relFormat.format(0, 'second');
+        } else {
+            for (const [ limit, options ] of absLimits) {
+                if (absDist >= limit) {
+                    return ts.toLocaleString(languageCode, options);
+                }
+            }
+            // We shouldn't be here
+            return ts.toLocaleString(languageCode, absLimits[absLimits.length - 1][1]);
+        }
+    };
+}]);