不需要模拟localStorage—只需使用jsdom环境，这样您的测试就可以在类似浏览器的条件下运行。

在你的joke。config。js中，

module.exports = {
    // ...
    testEnvironment: "jsdom"
}
    

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 

  
})

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。

上面的答案对我都没用。经过一番挖掘，这就是我要做的。这要归功于一些来源和其他答案。

https://www.codeblocq.com/2021/01/Jest-Mock-Local-Storage/ https://github.com/facebook/jest/issues/6798#issuecomment-440988627 https://gist.github.com/mayank23/7b994385eb030f1efb7075c4f1f6ac4c https://github.com/facebook/jest/issues/6798#issuecomment-514266034

我的全部要点:https://gist.github.com/ar-to/01fa07f2c03e7c1b2cfe6b8c612d4c6b

/**
 * Build Local Storage object
 * @see https://www.codeblocq.com/2021/01/Jest-Mock-Local-Storage/ for source
 * @see https://stackoverflow.com/a/32911774/9270352 for source
 * @returns
 */
export const fakeLocalStorage = () => {
  let store: { [key: string]: string } = {}

  return {
    getItem: function (key: string) {
      return store[key] || null
    },
    setItem: function (key: string, value: string) {
      store[key] = value.toString()
    },
    removeItem: function (key: string) {
      delete store[key]
    },
    clear: function () {
      store = {}
    },
  }
}

/**
 * Mock window properties for testing
 * @see https://gist.github.com/mayank23/7b994385eb030f1efb7075c4f1f6ac4c for source
 * @see https://github.com/facebook/jest/issues/6798#issuecomment-514266034 for sample implementation
 * @see https://developer.mozilla.org/en-US/docs/Web/API/Window#properties for window properties
 * @param { string } property window property string but set to any due to some warnings
 * @param { Object } value for property
 *
 * @example
 *
 *  const testLS = {
 *    id: 5,
 *    name: 'My Test',
 *  }
 * mockWindowProperty('localStorage', fakeLocalStorage())
 * window.localStorage.setItem('currentPage', JSON.stringify(testLS))
 *
 */
const mockWindowProperty = (property: string | any, value: any) => {
  const { [property]: originalProperty } = window
  delete window[property]
  beforeAll(() => {
    Object.defineProperty(window, property, {
      configurable: true,
      writable: true,
      value,
    })
  })
  afterAll(() => {
    window[property] = originalProperty
  })
}

export default mockWindowProperty

@chiedo的好解决方案

然而，我们使用ES2015语法，我觉得这样写会更简洁一些。

class LocalStorageMock {
  constructor() {
    this.store = {};
  }

  clear() {
    this.store = {};
  }

  getItem(key) {
    return this.store[key] || null;
  }

  setItem(key, value) {
    this.store[key] = String(value);
  }

  removeItem(key) {
    delete this.store[key];
  }
}

global.localStorage = new LocalStorageMock;

2021年,打印稿

class LocalStorageMock {
  store: { [k: string]: string };
  length: number;

  constructor() {
    this.store = {};
    this.length = 0;
  }

  /**
   * @see https://developer.mozilla.org/en-US/docs/Web/API/Storage/key
   * @returns
   */
  key = (idx: number): string => {
    const values = Object.values(this.store);
    return values[idx];
  };

  clear() {
    this.store = {};
  }

  getItem(key: string) {
    return this.store[key] || null;
  }

  setItem(key: string, value: string) {
    this.store[key] = String(value);
  }

  removeItem(key: string) {
    delete this.store[key];
  }
}

export default LocalStorageMock;

然后你可以用它

global.localStorage = new LocalStorageMock();