event filters and paging

src/app/services/event.service.ts

@@ -0,0 +1,38 @@
+import { Injectable } from '@angular/core';
+
+import { I18nService } from 'jslib/abstractions/i18n.service';
+
+@Injectable()
+export class EventService {
+    constructor(private i18nService: I18nService) { }
+
+    getDefaultDateFilters() {
+        const d = new Date();
+        const end = new Date(d.getFullYear(), d.getMonth(), d.getDate(), 23, 59);
+        d.setDate(d.getDate() - 30);
+        const start = new Date(d.getFullYear(), d.getMonth(), d.getDate(), 0, 0);
+        return [this.toDateTimeLocalString(start), this.toDateTimeLocalString(end)];
+    }
+
+    formatDateFilters(filterStart: string, filterEnd: string) {
+        const start: Date = new Date(filterStart);
+        const end: Date = new Date(filterEnd + ':59.999');
+        if (isNaN(start.getTime()) || isNaN(end.getTime()) || end < start) {
+            throw new Error('Invalid date range.');
+        }
+        return [start.toISOString(), end.toISOString()];
+    }
+
+    private toDateTimeLocalString(date: Date) {
+        return date.getFullYear() +
+            '-' + this.pad(date.getMonth() + 1) +
+            '-' + this.pad(date.getDate()) +
+            'T' + this.pad(date.getHours()) +
+            ':' + this.pad(date.getMinutes());
+    }
+
+    private pad(num: number) {
+        const norm = Math.floor(Math.abs(num));
+        return (norm < 10 ? '0' : '') + norm;
+    }
+}