Reworks date parsing, formatting etc for perf

Isolates moment.js

src/system/date.ts

@@ -0,0 +1,33 @@
+'use strict';
+import * as moment from 'moment';
+
+const MillisecondsPerMinute = 60000; // 60 * 1000
+const MillisecondsPerDay = 86400000; // 24 * 60 * 60 * 1000
+
+export namespace Dates {
+
+    export interface IDateFormatter {
+        fromNow: () => string;
+        format: (format: string) => string;
+    }
+
+    export function dateDaysFromNow(date: Date, now: number = Date.now()) {
+        const startOfDayLeft = startOfDay(now);
+        const startOfDayRight = startOfDay(date);
+
+        const timestampLeft = startOfDayLeft.getTime() - startOfDayLeft.getTimezoneOffset() * MillisecondsPerMinute;
+        const timestampRight = startOfDayRight.getTime() - startOfDayRight.getTimezoneOffset() * MillisecondsPerMinute;
+
+        return Math.round((timestampLeft - timestampRight) / MillisecondsPerDay);
+    }
+
+    export function startOfDay(date: Date | number) {
+        const newDate = new Date(typeof date === 'number' ? date : date.getTime());
+        newDate.setHours(0, 0, 0, 0);
+        return newDate;
+    }
+
+    export function toFormatter(date: Date): IDateFormatter {
+        return moment(date);
+    }
+}