Mocking react-router-dom hooks using jest is not working

Question

I'm using Enzyme's shallow method to test a component which uses the useParams hook to get an ID from the URL params.

I'm trying to mock the useParams hook so that it does't call the actual method, but it doesn't work. I'm still getting TypeError: Cannot read property 'match' of undefined, so it calls the actual useParams, and not my mock.

My component:

import React from 'react';
import { useParams } from 'react-router-dom';

export default () => {

  const { id } = useParams();

  return <div>{id}</div>;

};

Test:

import Enzyme from 'enzyme';
import Adapter from 'enzyme-adapter-react-16';
import React from 'react';
import Header from './header';
import { shallow } from 'enzyme';

Enzyme.configure({ adapter: new Adapter() });

describe('<Header />', () => {

  jest.mock('react-router-dom', () => ({
    useParams: jest.fn().mockReturnValue({ id: '123' }),
  }));

  it('renders', () => {
    const wrapper = shallow(<Header />);
    expect(wrapper).toBeTruthy();
  });

});

Thank you!

Answer 1

This works for me to mock useParams and change values for each unit test within the same file:

import React from "react";
import { render } from "@testing-library/react";
import Router from "react-router-dom";
import Component from "./Component";

jest.mock("react-router-dom", () => ({
 ...jest.requireActual("react-router-dom"),
 useParams: jest.fn(),
}));

const createWrapper = () => {
 return render(<Cases />);
};

describe("Component Page", () => {
 describe("Rendering", () => {
   it("should render cases container", () => {
     jest.spyOn(Router, 'useParams').mockReturnValue({ id: '1234' })
     const wrapper = createWrapper();
     expect(wrapper).toMatchSnapshot();
   });

   it("should render details container", () => {
     jest.spyOn(Router, 'useParams').mockReturnValue({ id: '5678' })
     const wrapper = createWrapper();
     expect(wrapper).toMatchSnapshot();
   });
 });
});

Just declare useParams as jest.fn() outside describe() and then change its values in each unit test with jest.spyOn

Answer 2

I am not sure why, also couldn't find it in the docs of react-router library, but changing react-router-dom to react-router in both tests and implementation worked for me.

So it becomes something like this:

import Enzyme from 'enzyme';
import Adapter from 'enzyme-adapter-react-16';
import React from 'react';
import Header from './header';
import { shallow } from 'enzyme';

Enzyme.configure({ adapter: new Adapter() });

describe('<Header />', () => {

  jest.mock('react-router', () => ({
    useParams: jest.fn().mockReturnValue({ id: '123' }),
  }));

  it('renders', () => {
    const wrapper = shallow(<Header />);
    expect(wrapper).toBeTruthy();
  });

});