describe('getToken', () => {
    const Auth = new AuthService();
    const token = 'eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJ1c2VybmFtZSI6Ik1yIEpvc2VwaCIsImlkIjoiNWQwYjk1Mzg2NTVhOTQ0ZjA0NjE5ZTA5IiwiZW1haWwiOiJ0cmV2X2pvc0Bob3RtYWlsLmNvbSIsInByb2ZpbGVVc2VybmFtZSI6Ii9tcmpvc2VwaCIsInByb2ZpbGVJbWFnZSI6Ii9Eb3Nlbi10LUdpci1sb29rLWN1dGUtbnVrZWNhdDMxNnMtMzExNzAwNDYtMTI4MC04MDAuanBnIiwiaWF0IjoxNTYyMzE4NDA0LCJleHAiOjE1OTM4NzYwMDR9.YwU15SqHMh1nO51eSa0YsOK-YLlaCx6ijceOKhZfQZc';
    beforeEach(() => {
        global.localStorage = jest.fn().mockImplementation(() => {
            return {
                getItem: jest.fn().mockReturnValue(token)
            }
        });
    });
    it('should get the token from localStorage', () => {

        const result  = Auth.getToken();
        expect(result).toEqual(token);

    });
});

创建一个模拟并将其添加到全局对象

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();

2022年的更新。

Jest@24+具有自动模拟本地存储的能力。但是，默认情况下，它不再附带所需的依赖项。

npm 和 -D 是 environment-jsdom

你还需要改变你的笑话测试模式:

// jest.config.cjs
module.exports = {
  ...
  testEnvironment: "jsdom",
  ...
};

现在localStorage已经被模拟了。

例子:

// myStore.js
const saveLocally = (key, value) => {
  localStorage.setItem(key, value)
};

测试:

// myStore.spec.ts
import { saveLocally } from "./myStore.js"

it("saves key-value pair", () => {
  let key = "myKey";
  let value = "myValue";
  expect(localStorage.getItem(key)).toBe(null);
  saveLocally(key, value);
  expect(localStorage.getItem(key)).toBe(value);
};

一个更好的替代方法，它处理未定义的值(它不需要toString())，如果值不存在则返回null。用react v15、redux和redux-auth-wrapper进行了测试

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

  clear() {
    this.store = {}
  }

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

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

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

global.localStorage = new LocalStorageMock

@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;

我从github找到了这个解决方案

var localStorageMock = (function() {
  var store = {};

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

Object.defineProperty(window, 'localStorage', {
 value: localStorageMock
});

您可以在setupTests中插入这段代码，它应该可以正常工作。

我在一个使用typesctipt的项目中测试了它。