How can I use setupFiles in Jest for advanced configurations?

How can I use setupFiles in Jest for advanced configurations?

You can use the setupFiles option in Jest to specify files that should be run before each test file. This is useful for setting up global variables or configurations.

Can you give me an example of a setup file?

Sure! A common example is to create a file named setupTests.js where you can configure Enzyme or set up global mocks.

How do I include this setup file in my Jest configuration?

You can include it in your Jest configuration by adding setupFiles: ['<rootDir>/setupTests.js'] in your jest.config.js.

What if I need to run some code only once before all tests?

In that case, you should use setupFilesAfterEnv instead of setupFiles. This runs the specified files after the test framework is installed but before the tests are executed.