Utility class to read and write arrays in localStorage / sessionStorage.

storageArray.ts

class StorageArray {
  private storage: Storage;

  constructor(storage: Storage) {
    this.storage = storage;
  }

  get(key: string): string[] | null {
    const jsonString = this.storage.getItem(key);

    if (!jsonString) {
      return null;
    }

    return JSON.parse(jsonString);
  }

  set(key: string, items: string[]) {
    const jsonString = JSON.stringify(items);
    this.storage.setItem(key, jsonString);
  }

  addItem(key: string, item: string) {
    const items = this.get(key) ?? [];
    items.push(item);
    this.set(key, items);
  }

  removeItem(key: string, item: string) {
    const items = this.get(key);

    if (!items) {
      return;
    }

    const index = items.indexOf(item);

    if (index < 0) {
      return;
    }

    items.splice(index, 1);
    this.set(key, items);
  }
}

export const localStorageArray = new StorageArray(localStorage);
export const sessionStorageArray = new StorageArray(sessionStorage);