Why are static methods in js bad?

Question

typescript

I am writing the front in Angular. There was a task to store filter data in localStore, for this I created a class with static methods:

export class FilterStorageUtil {
  private static storage = window.localStorage;
  private static prefix = 'StorageFilter-';

  public static setFilter<T extends object>(filter: T, key = location.pathname) {
    const itemKey = this.prefix + key;
    this.storage.setItem(itemKey, JSON.stringify(filter));
    return true;
  }

  public static getFilter(key = location.pathname) {
    const itemKey = this.prefix + key;
    const jsonFilter = this.storage.getItem(itemKey);
    try {
      return JSON.parse(jsonFilter);
    } catch (e) {
      return null;
    }
  }
}

My colleague told me that this is evil and you can’t write like that, supposedly eating memory, and you need to use services. To what extent is it justified?

Answer 1

Static methods in JS are great and save memory. Static methods in your code are bad, because in this particular case it is better to use a service.