When I want to switch from A tab to B then it shows blank page using cypress

Question

After login when I switch from Tab A to Tab B then it shows blank page, How i maintain session of Tab A. After performing activity on Tab A, I move to Tab B and start performing activity on Tab B

Answer 1

If the session has not been created yet, it will run the callback fn code, otherwise, it will only restore the session (and you'll have to visit the page again).

So, I think changing before hook to a beforeEach and adding a visit after the login method would work:

beforeEach(() => {
  login('user1')
  cy.visit('http://#')
})

But this approach will visit the page twice in the first run, to avoid this personally I would use the login with it's code in the before hook and restore and visit the page in the beforeEach.

const login = ({ sessionId, username, password }) => {
  cy.session(sessionId, () => {
    cy.visit('http://#')
    cy.get('[type=text]').type(username)
    cy.get('[type=password]').type(password)
    cy.get('[type=submit]').click()
  })
}

describe('test', () => {
  const sessionId = 'Login with valid credentials'

  before(() => {
    login({ sessionId, username: 'user1', password: 'Test123' })
  })

  beforeEach(() => {
    cy.session(sessionId)
    cy.visit('http://#')
  })

  it('Tab A', () => {
    cy.get('#A').click()
  })

  it('Tab B', () => {
    cy.get('#B').click()
  })
})

Please let me know if it solves your problem.