I like Jest so much because it provides an awesome experience when writing tests. I like so much the "expect" function, the assertion methods and the watch mode. I used Jest with the arrange-act-assert pattern, it was great.

Jest easy to set up with all react and react native project and comes as a default testing framework for "create-react-app". Its light and fast as its does parallellization and caching while running tests. It's one stop shop that comes with lot built in "expect" functionalities and flavours of "jasmine" makes ease writing test without imports Mocking is the heart beat of writing unit tests and jest makes it easier by providing module level mocks features and libraries. It's an interactive mode with lot of shortcuts makes easy to run specific test or test file and its allows to test only latest commit changes with git interaction watch mode The ide called Vscode has jest plugin which makes testing even more faster.

Jest is very useful and very important tool to have for testing javascript code. The feature about this tool i like the most is its ability to test multiple classes at once and even a single test can be run through it.