mempool/frontend/src/app/services/storage.service.ts

import { Injectable } from '@angular/core';
import { Router, ActivatedRoute } from '@angular/router';

@Injectable({
  providedIn: 'root'
})
export class StorageService {
  constructor(private router: Router, private route: ActivatedRoute) {
    this.setDefaultValueIfNeeded('graphWindowPreference', '2h');
    this.setDefaultValueIfNeeded('poolsWindowPreference', '1d');
  }

  setDefaultValueIfNeeded(key: string, defaultValue: string) {
    let graphWindowPreference: string = this.getValue(key);
    if (graphWindowPreference === null) { // First visit to mempool.space
      if (this.router.url.includes("graphs") || this.router.url.includes("pools")) {
        this.setValue(key, this.route.snapshot.fragment ? this.route.snapshot.fragment : defaultValue);
      } else {
        this.setValue(key, defaultValue);
      }
    } else if (this.router.url.includes("graphs") || this.router.url.includes("pools")) { // Visit a different graphs#fragment from last visit
      if (this.route.snapshot.fragment !== null && graphWindowPreference !== this.route.snapshot.fragment) {
        this.setValue(key, this.route.snapshot.fragment);
      }
    }
  }

  getValue(key: string): string {
    try {
      return localStorage.getItem(key);
    } catch (e) {
      console.log(e);
      return '';
    }
  }

  setValue(key: string, value: any): void {
    try {
      localStorage.setItem(key, value);
    } catch (e) {
      console.log(e);
    }
  }
}