Jest. Test coverage option

Ilya Zykin
2 min readJul 17, 2020

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Here I’ll tell you about how to get a test coverage metric for an application where you use Jest for unit tests.

I’m joining a new project where a lot of code and tests. I found there is no too much information about how much tests are written and how well they cover the project. Let’s change that.

I found, it’s super easy to add coverage information with adding the following group of configurations in jest.config.js file

After I have run specs I see the report

If I go to the folder coverage/unit there I see an HTML report

I can click on a file and see uncovered places.

Looks just great!

Have a happy development!

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Ilya Zykin

IT coach. React and Rails enthusiast. Passionate programmer, caring husband and pancake baker on Sundays. School teacher of computer studies in the past.