services.js

import angular from 'angular';
angular.module('todo').factory('todoStorage', function () {
  var TODO_DATA = 'TODO_DATA';
  var storage = {
    todos: [],
    _saveToLocalStorage: function (data) {
      localStorage.setItem(TODO_DATA, JSON.stringify(data));
    },
    _getFromLocalStorage: function () {
      return JSON.parse(localStorage.getItem(TODO_DATA)) || []; 
    },
    get: function () {
      angular.copy(storage._getFromLocalStorage(), storage.todos);
      return storage.todos;
    },
    remove: function (todo) {
      var idx = storage.todos.findIndex(function (item) {
        return item.id === todo.id;
      });

      if (idx > -1) {
        storage.todos.splice(idx, 1);
        storage._saveToLocalStorage(storage.todos);
      }
    },
    add: function (newTodoTitle) {
      var newTodo = {
        title: newTodoTitle,
        completed: false,
        createdAt: Date.now(),
      };

      storage.todos.push(newTodo);
      storage._saveToLocalStorage(storage.todos);
    },
    update: function(){
      storage._saveToLocalStorage(storage.todos);
    }
  }
  return storage;
});