angular-challenges/apps/performance/christmas-web-worker/src/app/heavy-calculation.service.ts

import { Injectable, computed, signal } from '@angular/core';

@Injectable()
export class HeavyCalculationService {
  private finalLength = 664579;
  private loadingLength = signal(0);

  loadingPercentage = computed(
    () => (this.loadingLength() * 100) / this.finalLength
  );

  startLoading() {
    this.randomHeavyCalculalationFunction();
  }

  private randomHeavyCalculalationFunction() {
    for (let num = 2; num <= 10000000; num++) {
      let randomFlag = true;
      for (let i = 2; i <= Math.sqrt(num); i++) {
        if (num % i === 0) {
          randomFlag = false;
          break;
        }
      }
      if (randomFlag) {
        this.loadingLength.update((l) => l + 1);
      }
    }
  }
}