Refactor accelerator dashboard

frontend/src/app/components/acceleration/pending-stats/pending-stats.component.ts

@@ -0,0 +1,39 @@
+import { ChangeDetectionStrategy, Component, Input, OnInit } from '@angular/core';
+import { Observable, of } from 'rxjs';
+import { switchMap } from 'rxjs/operators';
+import { ApiService } from '../../../services/api.service';
+
+@Component({
+  selector: 'app-pending-stats',
+  templateUrl: './pending-stats.component.html',
+  styleUrls: ['./pending-stats.component.scss'],
+  changeDetection: ChangeDetectionStrategy.OnPush,
+})
+export class PendingStatsComponent implements OnInit {
+  public accelerationStats$: Observable<any>;
+
+  constructor(
+    private apiService: ApiService,
+  ) { }
+
+  ngOnInit(): void {
+    this.accelerationStats$ = this.apiService.getAccelerations$().pipe(
+      switchMap(accelerations => {
+        let totalAccelerations = 0;
+        let totalFeeDelta = 0;
+        let totalVsize = 0;
+        for (const acceleration of accelerations) {
+          totalAccelerations++;
+          totalFeeDelta += acceleration.feeDelta || 0;
+          totalVsize += acceleration.effectiveVsize || 0;
+        }
+        return of({
+          count: totalAccelerations,
+          totalFeeDelta,
+          avgFeeDelta: totalAccelerations ? totalFeeDelta / totalAccelerations : 0,
+          totalVsize,
+        });
+      })
+    );
+  }
+}