What is the purpose of `beforeEach` global in Jest?

Question

I always find Jest-Enzyme test cases starting with a beforeEach global that resembles like the following:

describe(\'TEST BLOCK\' () => {
  let w         


        

Answer 1

Jest documentation recommends beforeEach for tests that consume a particular global state for each test, for example, resetting test data in a database before each test is run.

Note the following case:

If beforeEach is inside a describe block, it runs for each test in the describe block.

Using the same example where we have a database with test data, if your tests do not need the test data reset for each test, you can use beforeAll to run some code once, before any tests run.