这对我很有效，

delete global.localStorage;
global.localStorage = {
getItem: () => 
 }

在我的例子中，我需要在检查localStorage值之前设置它。

我所做的就是

const data = { .......}

const setLocalStorageValue = (name: string, value: any) => {
  localStorage.setItem(name, JSON.stringify(value))
}



 describe('Check X class', () => {
  setLocalStorageValue('Xname', data)
  const xClass= new XClass()

  console.log(xClass.initiate()) ; // it will work 

  
})

这对我来说是可行的，只需要一行代码

const setItem = jest.spyOn(Object.getPrototypeOf(localStorage)， 'setItem');

不幸的是，我在这里找到的解决方案对我不起作用。

所以我在看Jest GitHub的问题，发现了这个帖子

得到最多好评的解决方案是:

const spy = jest.spyOn(Storage.prototype, 'setItem');

// or

Storage.prototype.getItem = jest.fn(() => 'bla');

2022年12月:Nx 14使用Angular 14 Jest。 我们有一个测试设置。Ts文件在每个app和libs文件夹。我们设置本地存储模拟全局。

import 'jest-preset-angular/setup-jest';

Storage.prototype.getItem = jest.fn();
Storage.prototype.setItem = jest.fn();
Storage.prototype.removeItem = jest.fn();

然后localStorage.service.spec.ts文件如下所示:

import { LocalStorageService } from './localstorage.service';

describe('LocalStorageService', () => {
    let localStorageService: LocalStorageService;

    beforeEach(() => {
        localStorageService = new LocalStorageService();
    });

    it('should set "identityKey" in localStorage', async () => {
        localStorageService.saveData('identityKey', '99');
        expect(window.localStorage.setItem).toHaveBeenCalled();
 expect(window.localStorage.setItem).toHaveBeenCalledWith('identityKey', '99');
        expect(window.localStorage.setItem).toHaveBeenCalledTimes(1);
});

it('should get "identityKey" from localStorage', async () => {
    localStorageService.getData('identityKey');
    expect(window.localStorage.getItem).toHaveBeenCalled();
    expect(window.localStorage.getItem).toHaveBeenCalledWith('identityKey');
    expect(window.localStorage.getItem).toHaveBeenCalledTimes(1);
});

it('should remove "identityKey" from localStorage', async () => {
    localStorageService.removeData('identityKey');
    expect(window.localStorage.removeItem).toHaveBeenCalled();
expect(window.localStorage.removeItem).toHaveBeenCalledWith('identityKey');
            expect(window.localStorage.removeItem).toHaveBeenCalledTimes(1);
        });
    });

注:不好意思，这个SatckOverflow窗口很糟糕。

或者你只是像这样使用一个模拟包:

https://www.npmjs.com/package/jest-localstorage-mock

它不仅处理存储功能，还允许您测试是否实际调用了存储。