Develop Reference

While retrieving the dataStore.js object throws undefined in js file

I have created a dataStore.js object and tried to pass below string to object as below.
Getting undefined while console.log in Home.js, could someone please advise the issue here.
let dataStore = {
globaldata1: {},
globaldata2: {}
}
export { dataStore }
// profile.js
let datastore = require("../global/dataStore");
let myStr1 = "This is a string" ;
let myStr2 = "This is another string" ;
datastore.globaldata1 = myStr1;
datastore.globaldata2 = myStr2;
// home.js
let datastore = require("../global/dataStore");
let globalStr1 = datastore.globaldata1 ;
console.log("Print the data::"+globalStr1);
let globalStr2 = datastore.globaldata2 ;
console.log("Print the second data::"+globalStr2);
Applied the same concept in my Cypress tests:
Cypress version : v10.2.0
//dataStore.js
let dataStore = {
globaldata: {}
}
export { dataStore }
//site.Cy.js file
let dataStore = require("../../../support/dataStore");
import "cypress-localstorage-commands";
describe('Verify the Global data saving', () => {
context('Global data', () => {
beforeEach(() => {
cy.restoreLocalStorage();
cy.visit('/');
});
it('First get the text and Save globally', () => {
cy.get('#companyNameDiv > span').invoke('text').then((text)=>{
dataStore.globaldata = text;
console.log("First test outcome:: " +dataStore.globaldata); // all good here
});
});
it('Use that text in second test', () => {
console.log("Yeh, global text in second test :: " +dataStore.globaldata ); // all good here
});
});
});
//another.Cy.js file
let dataStore = require("../../../support/dataStore");
import "cypress-localstorage-commands";
describe('Retrive another test file', () => {
context('Retrive saved data in another test file', () => {
it('Get the text', () => {
console.log("Yeh, another test file:: " +dataStore.globaldata);
// here I am getting the text as undefined ??
});
});
});

Checking out the Cypress tests, with some slight mods for folder paths and different baseUrl.
Since Cypress v10 no longer has "Run all" option I also added a barrel spec called all.cy.js which allows running multiple specs and also enforces the order of the spec (which would be important for this to work).
The test worked ok in cypress open then selecting all.cy.js and also cypress run --spec cypress/e2e/all.cy.js.
all.cy.js
import './site.cy.js'
import './another.cy.js'
site.cy.js
let dataStore = require("../support/dataStore");
import "cypress-localstorage-commands";
describe('Verify the Global data saving', () => {
context('Global data', () => {
beforeEach(() => {
cy.restoreLocalStorage();
cy.visit('http://example.com')
});
it('First get the text and Save globally', () => {
// cy.get('#companyNameDiv > span').invoke('text').then((text)=>{
const text = 'this is my text'
dataStore.globaldata = text;
console.log("First test outcome:: " +dataStore.globaldata); // all good here
// });
});
it('Use that text in second test', () => {
console.log("Yeh, global text in second test :: " +dataStore.globaldata ); // all good here
});
});
});
another.cy.js
let dataStore = require("../support/dataStore");
import "cypress-localstorage-commands";
describe('Retrive another test file', () => {
context('Retrive saved data in another test file', () => {
it('Get the text', () => {
console.log("Yeh, another test file:: " +dataStore.globaldata);
expect(dataStore.globaldata).to.eq('this is my text') // ✅ passes
});
});
});

It would seem the issue here is that you didn't properly capitalize your import.
Your export from dataStore.js is:
export { dataStore }
Where the S is capitalized, but in your Home.js:
const { datastore } = reqiure(...)
It doesn't have a capitalized S which would make the import undefined because dataStore.js doesn't export datastore, it exports dataStore

Jest with axios in window.api in Vue [duplicate]

I need to test a function which opens a new tab in the browser
openStatementsReport(contactIds) {
window.open(`a_url_${contactIds}`);
}
I would like to mock window's open function, so I can verify the correct URL is passed in to the open function.
Using Jest, I don't know how to mock window. I tried to set window.open with a mock function, but this way doesn't work. Below is the test case:
it('the correct URL is called', () => {
window.open = jest.fn();
statementService.openStatementsReport(111);
expect(window.open).toBeCalled();
});
But it gives me the error
expect(jest.fn())[.not].toBeCalled()
jest.fn() value must be a mock function or spy.
Received:
function: [Function anonymous]
What should I do to the test case?

The following method worked for me. This approach allowed me to test some code that should work both in the browser and in Node.js, as it allowed me to set window to undefined.
This was with Jest 24.8 (I believe):
let windowSpy;
beforeEach(() => {
windowSpy = jest.spyOn(window, "window", "get");
});
afterEach(() => {
windowSpy.mockRestore();
});
it('should return https://example.com', () => {
windowSpy.mockImplementation(() => ({
location: {
origin: "https://example.com"
}
}));
expect(window.location.origin).toEqual("https://example.com");
});
it('should be undefined.', () => {
windowSpy.mockImplementation(() => undefined);
expect(window).toBeUndefined();
});

Instead of window, use global:
it('the correct URL is called', () => {
global.open = jest.fn();
statementService.openStatementsReport(111);
expect(global.open).toBeCalled();
});
You could also try:
const open = jest.fn()
Object.defineProperty(window, 'open', open);

There are a couple of ways to mock globals in Jest:
Use the mockImplementation approach (the most Jest-like way), but it will work only for those variables which has some default implementation provided by jsdom. window.open is one of them:
test('it works', () => {
// Setup
const mockedOpen = jest.fn();
// Without making a copy, you will have a circular dependency problem
const originalWindow = { ...window };
const windowSpy = jest.spyOn(global, "window", "get");
windowSpy.mockImplementation(() => ({
...originalWindow, // In case you need other window properties to be in place
open: mockedOpen
}));
// Tests
statementService.openStatementsReport(111)
expect(mockedOpen).toBeCalled();
// Cleanup
windowSpy.mockRestore();
});
Assign the value directly to the global property. It is the most straightforward, but it may trigger error messages for some window variables, e.g. window.href.
test('it works', () => {
// Setup
const mockedOpen = jest.fn();
const originalOpen = window.open;
window.open = mockedOpen;
// Tests
statementService.openStatementsReport(111)
expect(mockedOpen).toBeCalled();
// Cleanup
window.open = originalOpen;
});
Don't use globals directly (requires a bit of refactoring)
Instead of using the global value directly, it might be cleaner to import it from another file, so mocking will became trivial with Jest.
File ./test.js
jest.mock('./fileWithGlobalValueExported.js');
import { windowOpen } from './fileWithGlobalValueExported.js';
import { statementService } from './testedFile.js';
// Tests
test('it works', () => {
statementService.openStatementsReport(111)
expect(windowOpen).toBeCalled();
});
File ./fileWithGlobalValueExported.js
export const windowOpen = window.open;
File ./testedFile.js
import { windowOpen } from './fileWithGlobalValueExported.js';
export const statementService = {
openStatementsReport(contactIds) {
windowOpen(`a_url_${contactIds}`);
}
}

I'm directly assigning jest.fn() to window.open.
window.open = jest.fn()
// ...code
expect(window.open).toHaveBeenCalledTimes(1)
expect(window.open).toHaveBeenCalledWith('/new-tab','_blank')

In my component I need access to window.location.search. This is what I did in the Jest test:
Object.defineProperty(global, "window", {
value: {
location: {
search: "test"
}
}
});
In case window properties must be different in different tests, we can put window mocking into a function, and make it writable in order to override for different tests:
function mockWindow(search, pathname) {
Object.defineProperty(global, "window", {
value: {
location: {
search,
pathname
}
},
writable: true
});
}
And reset after each test:
afterEach(() => {
delete global.window.location;
});

We can also define it using global in setupTests:
// File 'setupTests.js'
global.open = jest.fn()
And call it using global in the actual test:
// File 'yourtest.test.js'
it('the correct URL is called', () => {
statementService.openStatementsReport(111);
expect(global.open).toBeCalled();
});

I found an easy way to do it: delete and replace
describe('Test case', () => {
const { open } = window;
beforeAll(() => {
// Delete the existing
delete window.open;
// Replace with the custom value
window.open = jest.fn();
// Works for `location` too, eg:
// window.location = { origin: 'http://localhost:3100' };
});
afterAll(() => {
// Restore original
window.open = open;
});
it('correct url is called', () => {
statementService.openStatementsReport(111);
expect(window.open).toBeCalled(); // Happy happy, joy joy
});
});

The window object in Jest is self-mocking
One of the things unaddressed in other answers is a comment by the OP:
Using Jest, I don't know how to mock the window.
The window object is already mocked and can be referenced out of the box.
From the documentation:
Jest ships with jsdom which simulates a DOM environment as if you were in the browser. This means that every DOM API that we call can be observed in the same way it would be observed in a browser!
Example:
describe('i am a window', () => {
it('has a window object', () => {
expect(window).toBeTruthy(); // test will pass
});
});

You can try this:
import * as _Window from "jsdom/lib/jsdom/browser/Window";
window.open = jest.fn().mockImplementationOnce(() => {
return new _Window({ parsingMode: "html" });
});
it("correct url is called", () => {
statementService.openStatementsReport(111);
expect(window.open).toHaveBeenCalled();
});

If it's similar to the window location problem at window.location.href can't be changed in tests. #890, you could try (adjusted):
delete global.window.open;
global.window = Object.create(window);
global.window.open = jest.fn();

In your Jest configuration, add setupFilesAfterEnv: ["./setupTests.js"], create that file, and add the code you want to run before the tests:
// setupTests.js
window.crypto = {
.....
};
Reference: setupFilesAfterEnv [array]

Try simply:
let windowOpenSpy: jest.SpyInstance;
beforeEach(() => {
windowOpenSpy = jest.spyOn(window, 'open');
});
it('should open window with dashboard url', () => {
expect(windowOpenSpy).toBeCalledWith('your URL', '_blank');
});

I have a utility function which allows me to mock any method on the window like so:
function givenMockWindowMethods(methods: Partial<{ [key in keyof Window]: jest.Mock<any, any> }>): () => void {
const mocks = Object.values(methods);
Object.entries(methods).forEach(([key, value]) => {
Object.defineProperty(window, key, { value });
});
return (): void => mocks.forEach((mock) => mock?.mockClear());
}
So if I need to mock the open method (or anything really) on the window, I can do:
const cleanupMocks = givenMockWindowMethods({ open: jest.fn() });
// expect(...).toBe(...)
//at the end of the test, clean it up
cleanupMocks()

You can test it:
describe('TableItem Components', () => {
let open_url = ""
const { open } = window;
beforeAll(() => {
delete window.open;
window.open = (url) => { open_url = url };
});
afterAll(() => {
window.open = open;
});
test('string type', async () => {
wrapper.vm.openNewTab('http://example.com')
expect(open_url).toBe('http://example.com')
})
})

const windowSpy = jest.spyOn(iFrame, "contentWindow", "get");
windowSpy.mockImplementation(() => ({
location: {
origin: "https://test.com",
href: "href",
hash: "hash"
}
}));

I tried a similar test, and it worked with me...
My code:
export const Blah = () => {
const BLAH = 'https://www.google.com/'
const handleBlah = () => {
window.open(BLAH, '_blank')
}
return (
<button onClick={handleBlah}> BLAHBLAH </button>
)
}
My test using Jest:
it('should be able to render "BLAHBLAH " button ', () => {
window.open = jest.fn();
const BLAH = 'https://www.google.com/'
const { getByText } = render(<Blah/>) // Get text by my page Blah
const buttonGoToBlah = getByText('BLAHBLAH') // Get button by text
fireEvent.click(buttonGoToBlah) // Simulate the click event
expect(window.open).toHaveBeenCalledTimes(1) // Expect the window.open have to been called at least once.
expect(window.open).toHaveBeenCalledWith(BLAH, '_blank'); // And the page should be the same called in my BLAH page
})

Return a double in Jest JS

I have a simple function like this that I want to test:
const saveAs = (fileName, content, contentType) => {
const a = createDownloadLink(fileName, content, contentType)
a.click()
}
export const createDownloadLink = (fileName, content, contentType) => {
...
const a = document.createElement('a')
...
return a
}
export default saveAs
I want to test that when I call saveAs, createDownloadLink is called, and click is called on the result.
I have tried mocking createDownloadLink and creating a spy on it. However, I can't find how to test click on the result:
Jest JS test:
const createDownloadLink = jest.fn()
saveAs('file.html', '<h1>hello</h1>', 'test/plain;UTF-8')
expect(createDownloadLink).toBeCalled() // And return a double
// expect(double.click).toBeCalled
})

I know you have already answered your own question, but since you've stated you didn't like seperating your functionality in two files I may have an alternative solution. Since you are exporting both functions anyways may I propose you actually make both part of the same object? This would allow you to mock or spy on the module function easily. For example lets assume you have saver.js:
class Saver {
saveAs(fileName, content, contentType) {
const a = this.createDownloadLink(fileName, content, contentType)
a.click()
}
createDownloadLink(fileName, content, contentType) {
const a = document.createElement('a')
return a
}
}
const saver = new Saver();
export default saver;
Then you your test would look like this:
import saver from './saver'
describe('saveAs', () => {
it("calls click on download link", () => {
const click = jest.fn()
saver.createDownloadLink = jest.fn(() => ({ click }));
saver.saveAs('file.html', '<h1>hello</h1>', 'test/plain;UTF-8')
expect(click).toHaveBeenCalled();
})
})

I finally solved this by creating an intermediate object that I use as a double.
Unfortunately, I had to separate my functionality into 2 files in order to use `jest.mock.
import saveAs from './index'
import createDownloadLink from './utils'
jest.mock("./utils");
describe('saveAs', () => {
it("calls click on download link", () => {
const downloadLinkDouble = {}
const clickMock = jest.fn()
downloadLinkDouble.click = clickMock
createDownloadLink.mockImplementation(() => downloadLinkDouble)
saveAs('file.html', '<h1>hello</h1>', 'test/plain;UTF-8')
expect(clickMock).toHaveBeenCalled()
})
})

Jest - mock a named class-export in typescript

I have a node module which exports a few classes, one of which is Client, which I use to create a client (having a few APIs as methods).
I'm trying to test my module which uses this node module as a dependency using Jest. However, I've been unable to successfully mock the one method (say search()) in the Client class.
Here is my spec for myModule:
//index.spec.ts
import * as nock from 'nock';
import * as externalModule from 'node-module-name';
import { createClient } from './../../src/myModule';
describe(() => {
beforeAll(() => {
nock.disableNetConnect();
});
it('test search method in my module', () => {
jest.mock('node-module-name');
const mockedClient = <jest.Mock<externalModule.Client>>externalModule.Client;
const myClient = createClient({/*params*/}); //returns instance of Client class present in node module by executing Client() constructor
myClient.searchByName('abc'); //calls search API - I need to track calls to this API
expect(mockedClient).toHaveBeenCalled();
expect(mockedClient.prototype.search).toHaveBeenCalledWith('abc');
});
});
This, however, doesn't create a mock at all and triggers a nock error since the search API tries to connect to the url (given through params).
I've also tried mocking the Client class like the following. While successfully creating a mock for the Client class and also the search API (verified that search() is also mocked through console logs), it gives me an error while I try to check if search() has been called.
externalModule.Client = jest.fn(() => { return { search: jest.fn(() => Promise.resolve('some response')) } });
//creates the mock successfully, but not sure how to track calls to 'search' property
const client = myModule.createClient(/*params*/);
client.searchByName('abc');
expect(externalModule.Client).toHaveBeenCalled(); //Successful
expect(externalModule.Client.prototype.search).toHaveBeenCalled(); //returns error saying "jest.fn() value must be a mock function or spy, Received: undefined"
I'm not sure what I'm doing wrong. Thank you in advance.

Mocking whole module
Try moving jest.mock to the top of file
//index.spec.ts
const search = jest.fn();
jest.mock('node-module-name', () => ({
Client: jest.fn(() => ({ search }))
}));
import * as nock from 'nock';
import * as externalModule from 'node-module-name';
import { createClient } from './../../src/myModule';
describe(() => {
beforeAll(() => {
nock.disableNetConnect();
});
it('test search method in my module', () => {
const myClient = createClient({/*params*/});
myClient.searchByName('abc');
expect(externalModule.Client).toHaveBeenCalled();
expect(search).toHaveBeenCalledWith('abc');
externalModule.Client.mockClear();
search.mockClear();
});
});
Mocking only Client
Create search constant and track it.
const search = jest.fn();
externalModule.Client = jest.fn(() => ({ search }));
const client = myModule.createClient(/*params*/);
client.searchByName('abc');
expect(externalModule.Client).toHaveBeenCalled();
expect(search).toHaveBeenCalled();

Here is how I mocked it. I had to change naming and removing some code to avoid exposing original source.
jest.mock('../foo-client', () => {
return { FooClient: () => ({ post: mockPost }) }
})
Full code.
// foo-client.ts
export class FooClient {
constructor(private config: any)
post() {}
}
// foo-service.ts
import { FooClient } from './foo-client'
export class FooLabelService {
private client: FooClient
constructor() {
this.client = new FooClient()
}
createPost() {
return this.client.post()
}
}
// foo-service-test.ts
import { FooService } from '../foo-service'
const mockPost = jest.fn()
jest.mock('../foo-client', () => {
return { FooClient: () => ({ post: mockPost }) }
})
describe('FooService', () => {
let fooService: FooService
beforeEach(() => {
jest.resetAllMocks()
fooService = new FooService()
})
it('something should happened', () => {
mockPost.mockResolvedValue()
fooService.createPost()
})
})

Jest URL.createObjectURL is not a function

I'm developping a reactJs application. I'm using jest to test my application.
I want to test a function that download a blob.
But unfortunately I receve this error:
URL.createObjectURL is not a function
my test function:
describe('download', () => {
const documentIntial = { content: 'aaa' };
it('msSaveOrOpenBlob should not have been called when navigao is undefined', () => {
window.navigator.msSaveOrOpenBlob = null;
download(documentIntial);
expect(window.navigator.msSaveOrOpenBlob).toHaveBeenCalledTimes(0);
});
});
The function I want to test:
export const download = document => {
const blob = new Blob([base64ToArrayBuffer(document.content)], {
type: 'application/pdf',
});
if (window.navigator && window.navigator.msSaveOrOpenBlob) {
window.navigator.msSaveOrOpenBlob(blob);
return;
}
const fileURL = URL.createObjectURL(blob);
window.open(fileURL);
};

This would appear to be as simple as setting up URL on the Global in Jest. Something like
describe('download', () => {
const documentIntial = { content: 'aaa' };
global.URL.createObjectURL = jest.fn();
it('msSaveOrOpenBlob should not have been called when navigao is undefined', () => {
global.URL.createObjectURL = jest.fn(() => 'details');
window.navigator.msSaveOrOpenBlob = jest.fn(() => 'details');
download(documentIntial);
expect(window.navigator.msSaveOrOpenBlob).toHaveBeenCalledTimes(1);
});
});
This should result in a test that you can also use for checking if global.URL.createObjectURL was called. As a side note: you may also run into a similar issue with window.open I would suggest mocking that as well if this becomes the case.

Since window.URL.createObjectURL is not (yet) available in jest-dom, you need to provide a mock implementation for it.
Don't forget to reset the mock implementation after each test.
describe("your test suite", () => {
window.URL.createObjectURL = jest.fn();
afterEach(() => {
window.URL.createObjectURL.mockReset();
});
it("your test case", () => {
expect(true).toBeTruthy();
});
});

jsdom, the JavaScript implementation of the WHATWG DOM used by jest doesn't implement this method yet.
You can find an open ticket about this exact issue on their github page where some workarounds are provided in comments. But if you need the blobURL to actually work you'll have to wait this FR is solved.
Workaround proposed in the comments of the issue for jest:
function noOp () { }
if (typeof window.URL.createObjectURL === 'undefined') {
Object.defineProperty(window.URL, 'createObjectURL', { value: noOp})
}

You just have to Write this in your setupTest.js
window.URL.createObjectURL = function() {};

The package jsdom-worker happens to provide this method, as well as adding support for web workers. The following worked for me:
npm install -D jsdom-worker
Then in package.json, edit or add a jest key:
{
...
"jest": {
"setupFiles": [
"jsdom-worker"
]
}
}

Just mocking the function global.URL.createObjectURL did not work for me, because the function was used by some modules during import and I got the error Jest URL.createObjectURL is not a function during import.
Instead it did help to create a file mockJsdom.js
Object.defineProperty(URL, 'createObjectURL', {
writable: true,
value: jest.fn()
})
Then import this file as the first import in your file containing the test
import './mockJsdom'
import { MyObjects} from '../../src/lib/mylib'
test('my test', () => {
// test code
}
Found here: https://jestjs.io/docs/manual-mocks#mocking-methods-which-are-not-implemented-in-jsdom