Where to put `beforeEach` for all test cases?

Question

What's the difference between these two tests:

beforeEach(doSomething)

describe("i am the only root describe in this test file", () => {
    // many test cases...
})

describe("i am the only root describe in this test file", () => {
    beforeEach(doSomething)
    // many test cases...
})

user_4803321 · Answer

If put beforeEach in a describe, it runs before each test in this block. If put it in the root level, it runs before all tests in all test files.