Is Jest used for unit testing?
Jest, the testing framework created by Facebook, is often used for unit testing. Jest performs very well, and allows for snapshot testing, which can be a great help when writing tests. Jest also offers easy mocking and assertions.
The biggest downside to Jest is that it is only for the JavaScript programming language. The term “unit testing” could be misleading because it implies that Jest does not work with any other languages. However, this is not true. Jest can be used with any language that follows the Node.js API.
https://www.xoriant.com/blog/product-engineering/jest-fast-furious-unit-testing-framework.html