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tmhao2005
tmhao2005

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Tip! Mock jsdom location with Jest

#javascript #testing #jest

Problem

In some cases, we have to call assign method of window.location object in order to redirect to a different url as below:

window.location.assign = '/home';
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You would receive an warning like below in case of jest running through above code:

Error: Not implemented: navigation (except hash changes)
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What is the solution here?

We obviously think about how to mock the location, right?

Here is the easiest way to do that:

const mockWinAssign = jest.fn(); const oldWindowLocation = window.location; beforeAll(() => { delete window.location; window.location = Object.defineProperties( {}, { ...Object.getOwnPropertyDescriptors(oldWindowLocation), assign: { configurable: true, value: mockWinAssign, }, }, ) }) afterAll(() => { // restore location window.location = oldWindowLocation; }) test('your test to call location method', () => { // do things // finally expect(mockWinAssign).toHaveBeenCalledWith('/home'); })
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