localstorage.js

/**********************************************************************************
 * (c) 2017, Nathanael Anderson.
 * Licensed under the MIT license.
 *
 * Version 1.1.5                                        nathan@master-technology.com
 **********************************************************************************/
'use strict';

var FileSystemAccess = require('file-system/file-system-access').FileSystemAccess;

// So that code that is looking for the "Storage" object will pass its check
if (!global.Storage) {
  global.Storage = function Storage() { }
}

if (!global.localStorage) {
  var localStorageData = {};
  var localStorageTimeout = null;

  var internalSaveData = function() {
    var fsa = new FileSystemAccess();
    var fileName = fsa.getDocumentsFolderPath() + "/localStorage.db";
    try {
      fsa.writeText(fileName, JSON.stringify(localStorageData));
    } catch (err) {
      // This should never happen on normal data, but if they tried to put non JS stuff it won't serialize
      console.log("localStorage: unable to write storage, error: ", err);
    }

  };

  var saveData = function()  {
    if (localStorageTimeout !== null) {
      clearTimeout(localStorageTimeout);
    }
    localStorageTimeout = setTimeout(internalSaveData, 250);
  };

  var loadData = function() {
    var fsa = new FileSystemAccess();
    var fileName = fsa.getDocumentsFolderPath() + "/localStorage.db";
    if (!fsa.fileExists(fileName)) {
      return;
    }

    var data;
    try {
      var textData = fsa.readText(fileName);
      data = JSON.parse(textData);
      localStorageData = data;
    }
    catch (err) {
      console.log("localStorage: error reading storage, Error: ", err);
    }
  };

  loadData();


  global.localStorage = {
    getItem: function (name) {
      if (localStorageData.hasOwnProperty(name)) {
        return localStorageData[name];
      }
      return null;
    },
    key: function(id) {
      var keys = Object.keys(localStorageData);
      if (id >= keys.length) { return null; }
      return keys[id];
    },
    setItem: function (name, value) {
      localStorageData[name] = value;
      saveData();
    },
    removeItem: function (name) {
      if (localStorageData[name]) {
        delete localStorageData[name];
        saveData();
      }
    },
    clear: function () {
      localStorageData = {};
      saveData();
    }
  };
  Object.defineProperty(global.localStorage, "length", {
    get: function() {
      return (Object.keys(localStorageData).length);
    },
    enumerable: true,
    configurable: true
  });
}


if (!global.sessionStorage) {
  var sessionStorageData = {};

  global.sessionStorage = {
    getItem: function (name) {
      if (sessionStorageData.hasOwnProperty(name)) {
        return sessionStorageData[name];
      }
      return null;
    },
    key: function(id) {
      var keys = Object.keys(sessionStorageData);
      if (id >= keys.length) { return null; }
      return keys[id];
    },
    setItem: function (name, value) {
      sessionStorageData[name] = value;
    },
    removeItem: function (name) {
      if (sessionStorageData[name]) {
        delete sessionStorageData[name];
      }
    },
    clear: function () {
      sessionStorageData = {};
    }
  };
  Object.defineProperty(global.sessionStorage, "length", {
    get: function() {
      return (Object.keys(sessionStorageData).length);
    },
    enumerable: true,
    configurable: true
  });
}

module.exports = global.localStorage;