Cypress examples (v13.8.1)

Stub Get TimeZone Offset Method

Let's say the application gets the current timezone using the method new Date().getTimezoneOffset() call. How do we stub it?

<output id="timezone" />
<script>
  setTimeout(() => {
    const tz = (new Date().getTimezoneOffset() / 60) * -1
    document.getElementById(
      'timezone',
    ).innerText = `TZ ${tz} hours`
  }, 100)
</script>

The method getTimezoneOffset comes from Date.prototype object.

cy.window()
  .its('Date.prototype')
  .then((datePrototype) => {
    cy.stub(datePrototype, 'getTimezoneOffset')
      .returns(900)
      .as('getTimezoneOffset')
  })
cy.contains('output', 'TZ -15 hours')

Confirm the method stub was called

cy.get('@getTimezoneOffset')
  .should('have.been.calledOnce')
  // optional: reset the stub to restore the original timezone
  .invoke('restore')

See also