Accessing aliases in Cypress with "this"

Question

I'm trying to share values between my before and beforeEach hooks using aliases. It currently works if my value is a string but when the value is an object, the alias is only defined in the first test, every test after that this.user is undefined in my beforeEach hook. How can I share a value which is an object between tests?

This is my code:

before(function() {
  const email = `test+${uuidv4()}@example.com`;
  cy
    .register(email)
    .its("body.data.user")
    .as("user");
});

beforeEach(function() {
  console.log("this.user", this.user); // This is undefined in every test except the first
});

Answer 1

The alias is undefined in every test except the first because aliases are cleared down after each test.

Aliased variables are accessed via cy.get('@user') syntax. Some commands are inherently asynchronous, so using a wrapper to access the variable ensures it is resolved before being used.

See documentation Variables and Aliases and get.

---

There does not seem to be a way to explicitly preserve an alias, as the is with cookies

Cypress.Cookies.preserveOnce(names...)

but this recipe for preserving fixtures shows a way to preserve global variables by reinstating them in a beforeEach()

let city
let country

before(() => {
  // load fixtures just once, need to store in
  // closure variables because Mocha context is cleared
  // before each test
  cy.fixture('city').then((c) => {
    city = c
  })

  cy.fixture('country').then((c) => {
    country = c
  })
})

beforeEach(() => {
  // we can put data back into the empty Mocha context before each test
  // by the time this callback executes, "before" hook has finished
  cy.wrap(city).as('city')
  cy.wrap(country).as('country')
})

---

If you want to access a global user value, you might try something like

let user;

before(function() {
  const email = `test+${uuidv4()}@example.com`;
  cy
    .register(email)
    .its("body.data.user")
    .then(result => user = result);
});

beforeEach(function() {
  console.log("global user", user); 
  cy.wrap(user).as('user');              // set as alias
});

it('first', () => {
  cy.get('@user').then(val => {
    console.log('first', val)            // user alias is valid
  })
})

it('second', () => {
  cy.get('@user').then(val => {
    console.log('second', val)           // user alias is valid
  })
})