accounts-frontend/packages/app/services/localStorage.ts

import logger from 'app/services/logger';

let _hasStorage = false;

try {
  const test = 'test';
  window.localStorage.setItem(test, test);
  window.localStorage.removeItem(test);

  _hasStorage = true;
} catch (err) {
  // bad luck, no storage available
  logger.info('No storage available'); // log for statistic purposes
}

export function hasStorage(): boolean {
  return _hasStorage;
}

class DummyStorage implements Storage {
  // FIXME: we can't use this declaration because it breaks react-hot-loader/babel
  // [key: string]: any;

  get length() {
    return Object.keys(this).length;
  }

  getItem(key: string): string | null {
    // @ts-ignore
    return this[key] || null;
  }

  setItem(key: string, value: string): void {
    // @ts-ignore
    this[key] = value;
  }

  removeItem(key: string): void {
    Reflect.deleteProperty(this, key);
  }

  clear(): void {
    Object.keys(this).forEach(this.removeItem);
  }

  key(index: number): string | null {
    return Object.keys(this)[index] || null;
  }
}

export const localStorage = _hasStorage
  ? window.localStorage
  : new DummyStorage();

export const sessionStorage = _hasStorage
  ? window.sessionStorage
  : new DummyStorage();

export default localStorage;