javascript - 错误 : getItem() method does not exist (Angular, 模拟 LocalStorage)

Question

我抓取了一段代码来模拟本地存储，但是，当我运行测试时，它抛出了这个错误。正如它所说，它找不到 getItem 方法，但我在 beforeEach block 之外显式声明了该方法。我不知道是什么引发了这个错误 - 希望得到提示和建议!

这是我的文件:

ma​​inCtrl.spec.js

describe('Controller: MainCtrl', function () {
  var store = {};
  var ls = function() {
    return JSON.parse(store.storage);
  };
  var localStorage = {}; 

  var getItem = function(key) {
    return store[key];
  }

  var setItem = function(key, value) {
    store[key] = value;
  }

  beforeEach(function() {
        // setUp.
        module('mytodoApp');

        // LocalStorage mock.
        spyOn(localStorage, 'getItem').andCallFake(getItem); <-- throwing the error
        Object.defineProperty(sessionStorage, "setItem", { writable: true });
        spyOn(localStorage, 'setItem').andCallFake(setItem);
    });

  afterEach(function() {
    store = {};
  });

  var MainCtrl,
    scope;

  // Initialize the controller and a mock scope
  beforeEach(inject(function ($controller, $rootScope) {
    scope = $rootScope.$new();
    MainCtrl = $controller('MainCtrl', {
      $scope: scope
    });
  }));

  it('should have no items to start with', function() {
    // expect(scope.todos.length).toBe(0);
    expect(Object.keys(store).length).toBe(0);
  });
});

ma​​inCtrl.js

angular.module('mytodoApp')
  .controller('MainCtrl', function ($scope, localStorageService) {
    //  breaks on repeat or blank input
    function addTodoFn() {
        $scope.todos.push($scope.todo); 
        $scope.todo = '';   
    }

    function removeTodoFn(index) {
        $scope.todos.splice(index, 1);
    }

    function watchFn() {
      localStorageService.set('todos', $scope.todos);
    }

    //////////

    var todosInStore = localStorageService.get('todos');
    $scope.todos = todosInStore || [];
    $scope.$watch('todos', watchFn, true);
    $scope.addTodo = addTodoFn;
    $scope.removeTodo = removeTodoFn;
  });

编辑

var localStorage = { 
    getItem: function(key) {
      return store[key];
    },

    setItem: function(key, value) {
      store[key] = value;
    }
  };

  beforeEach(function() {
    // setUp.
    module('mytodoApp');

    // LocalStorage mock.
    spyOn(localStorage, 'getItem').andCallFake(getItem);
    Object.defineProperty(sessionStorage, 'setItem', { writable: true });
    spyOn(localStorage, 'setItem').andCallFake(setItem);
  });

我按照@CosmicChild的建议进行了更改，但没有效果。

新错误消息

ReferenceError: Can't find variable: getItem

Answer 1

您需要在要 stub 的 localStorage 对象中定义一个空方法，

var localStorage = {
    getItem: function(key) {
    },
    setItem: function(key, value) {
    }
};