@applicaster/zapp-react-dom-app/Polyfills/Storage/index.js

Zapp App Component for Applicaster's Quick Brick React Native App

import * as R from "ramda";

import {
  noop,
  parseJsonIfNeeded,
} from "@applicaster/zapp-react-native-utils/functionUtils";
import { mapKeys } from "@applicaster/zapp-react-native-utils/objectUtils";

// export type StorageI = {
//   setItem: (string, string, ?string) => Promise<any>,
//   getItem: (string, ?string) => Promise<any>,
//   getAllItems: () => Promise<any>,
// };

export const STORAGE_TYPES = ["localStorage", "sessionStorage"];

export const DEFAULT_NAMESPACE = "applicaster.v2";

const NAMESPACE_SEPARATOR = "_::_";

/**
 * returns a key with the namespace, if provided
 * @param {String} key
 * @param {?String} namespace
 * @returns {String}
 */
export function applyNamespaceToKeyName(key, namespace) {
  return namespace ? `${namespace}${NAMESPACE_SEPARATOR}${key}` : key;
}

/**
 * this function will try to invoke a function,
 * run JSON.parse on its result, then resolve. If any error is caught
 * it will reject with the error. JSON parsing won't yield an error since we
 * use a method which will return its input if the parsing fails
 * @param {Function} fn function to run
 * @returns {Promise}
 */
function tryAndResolve(fn) {
  try {
    return R.compose(
      (value) => Promise.resolve(value),
      parseJsonIfNeeded,
      fn
    )();
  } catch (error) {
    return Promise.reject(error);
  }
}

/**
 * Gets a storage object from the window global object for web environment
 * if the storage type required is not implemented for some reason, a warning will
 * be sent, and a noop function will be returned. Will otherwise return an object with
 * methods to interact with the storage
 * @param {string} type of storage (localStorage or sessionStorage)
 * @returns {Object} storageObject
 * @returns {Function} storageObject.callMethod: invokes methods on the storage object
 * @returns {Function} storageObject.getKeys: returns all existing keys in the storage object
 */
function getStorageObject(type) {
  const storage = R.prop(type, window);

  if (!R.includes(type, STORAGE_TYPES) || !storage) {
    // eslint-disable-next-line no-console
    console.warn(`Storage type ${type} does not exist in this environment`);

    return {
      callMethod: noop,
    };
  }

  /**
   * calls a method on the storage object
   * @param {String} method to invoke
   * @param {Array} args array of arguments to use when invoking the method
   * @returns response of the method call
   */
  function callMethod(method, ...args) {
    return storage[method](...args);
  }

  /**
   * returns the list of keys in the storage object
   * @returns {Array<String>}
   */
  function getKeys() {
    // the test mock doesn't have exactly the same implementation for returning
    // allkeys, hence this check
    if (process.env.NODE_ENV === "test") {
      return storage.keys;
    }

    return R.keys(storage);
  }

  return {
    callMethod,
    getKeys,
  };
}

/**
 * returns an object to interact with a storage module (localStorage or sessionStorage)
 * @param {String} type of storage
 * @returns {StorageI}
 */
export function getStorageModule(type) {
  const Storage = getStorageObject(type);

  /**
   * sets an item in storage. Returns a promise which will
   * resolve to true if the value was set, or reject with an Error if not
   * @param {String} key
   * @param {String} value (already stringified)
   * @param {?String} namespace
   * @returns {Promise<Boolean|Error>}
   */
  function setItem(key, value, namespace = DEFAULT_NAMESPACE) {
    const keyName = applyNamespaceToKeyName(
      key,
      namespace || DEFAULT_NAMESPACE
    );

    return tryAndResolve(() => {
      Storage.callMethod("setItem", keyName, value);

      return true;
    });
  }

  /**
   * Retrieves an item from storage. Returns a promise which will resolve
   * with the value if it exists, or reject with an Error if not.
   * @param {String} key
   * @param {?String} namespace
   * @returns {Promise<Any|Error>}
   */
  function getItem(key, namespace = DEFAULT_NAMESPACE) {
    const keyName = applyNamespaceToKeyName(
      key,
      namespace || DEFAULT_NAMESPACE
    );

    return tryAndResolve(() => Storage.callMethod("getItem", keyName));
  }

  /**
   * Removes an item from storage. Returns a promise which will resolve
   * with a true value if it succeeds, or reject with an Error if not.
   * @param {String} key
   * @param {?String} namespace
   * @returns {Promise<Boolean|Error>}
   */
  function removeItem(key, namespace = DEFAULT_NAMESPACE) {
    const keyName = applyNamespaceToKeyName(key, namespace);

    return tryAndResolve(() => Storage.callMethod("removeItem", keyName));
  }

  /**
   * retrieves all items in storage, belonging to the namespace if provided
   * @param {?String} namespace
   * @returns {Promise<Object|Error>}
   */
  function getAllItems(namespace = null) {
    return tryAndResolve(() => {
      const keys = Storage.getKeys();

      const filteredKeys = R.filter(
        R.ifElse(
          () => namespace,
          (R.contains || R.includes)(`${namespace}${NAMESPACE_SEPARATOR}`),
          R.T
        ),
        keys
      );

      const getValuesForKeys = R.map((key) =>
        Storage.callMethod("getItem", key)
      );

      return Promise.all(getValuesForKeys(filteredKeys))
        .then(R.zipObj(filteredKeys))
        .then(
          mapKeys(
            R.replace(
              `${namespace || DEFAULT_NAMESPACE}${NAMESPACE_SEPARATOR}`,
              ""
            )
          )
        );
    });
  }

  return {
    setItem,
    getItem,
    getAllItems,
    removeItem,
  };
}