Jest unit test for a debounce function

Question

I am trying to write a unit test for a debounce function. I\'m having a hard time thinking about it.

This is the code:

Answer 1

If in your code you are doing so:

import debounce from 'lodash/debounce';

myFunc = debounce(myFunc, 300);

and you want to test the function myFunc or a function calling it, then in your test you can mock the implementation of debounce using jest to make it just return your function:

import debounce from 'lodash/debounce';

// Tell Jest to mock this import
jest.mock('lodash/debounce');

it('my test', () => {
    // ...
    debounce.mockImplementation(fn => fn); // Assign the import a new implementation. In this case it's to execute the function given to you
    // ...
});

Source: https://gist.github.com/apieceofbart/d28690d52c46848c39d904ce8968bb27