Safe localStorage & sessionStorage with JSON support

storage.js

const storage = type => ({
  /**
   * Asserts that sessionStorage or localStorage is available.
   *
   * Returns true even on quota exceeded error, so we won't silently ignore when we're using too much
   * space, unless we haven't stored anything yet which will happen when the browser has set a very
   * strict size limit (i.e. Safari Private Browsing sets quota to 0).
   *
   * @see https://developer.mozilla.org/en-US/docs/Web/API/Web_Storage_API/Using_the_Web_Storage_API
   */
  isAvailable() {
    let storage
    try {
      const x = "__storage_test__"
      storage = window[type]
      storage.setItem(x, x)
      storage.removeItem(x)
      return true
    } catch (e) {
      return (
        e instanceof window.DOMException &&
        (e.code === 22 ||
          e.code === 1014 ||
          e.name === "QuotaExceededError" ||
          e.name === "NS_ERROR_DOM_QUOTA_REACHED") &&
        (storage && storage.length !== 0)
      )
    }
  },

  /**
   * Retrieve an item from localStorage.
   *
   * @param {string} key Item key
   * @return {string} The item value, or undefined if not found
   */
  getItem(key) {
    try {
      return window[type] && window[type].getItem(key)
    } catch (e) {
      console.error(e)
    }
  },

  /**
   * Store an item in localStorage, checking for availability.
   *
   * @param {string} key Item key
   * @param {string} value Item value
   * @return {boolean} true if succeeded, false otherwise
   */
  setItem(key, value) {
    try {
      this.isAvailable() && window[type].setItem(key, value)
      return true
    } catch (e) {
      console.error(e)
      return false
    }
  },

  /**
   * Remove an item from localStorage.
   *
   * @param {string} key Item key
   * @return {void}
   */
  removeItem(key) {
    try {
      return window[type] && window[type].removeItem(key)
    } catch (e) {
      console.error(e)
    }
  },

  /**
   * Retrieve an object from localStorage, using JSON deserialization.
   *
   * @param {string} key Item key
   * @return {string|array|object}
   */
  getJson(key) {
    try {
      const item = this.getItem(key)
      return item && JSON.parse(item)
    } catch (e) {
      console.error(e)
    }
  },

  /**
   * Store an object in localStorage using JSON serialization.
   *
   * @param {any} key Item key
   * @param {string|array|object} data Item value, must be JSON-serializable
   * @return {boolean} true if succeeded, false otherwise
   */
  setJson(key, data) {
    try {
      return this.setItem(key, JSON.stringify(data))
    } catch (e) {
      console.error(e)
      return false
    }
  },
})

export const localStorage = storage("localStorage")
export const sessionStorage = storage("sessionStorage")