Visit command does not call the onBeforeLoad function

[delomer]

Current behavior:

onBeforeLoad does not working!

this example:

it('onload', function() {
  cy.on('window:before:load', e => {
    console.log('window:before:load');
  });

  cy.on('window:load', e => {
    console.log('window:load');
  });

  cy.visit('/', {
    onBeforeLoad(win) {
      console.log('onBeforeLoad');
    },
    onLoad(win) {
      console.log('onLoad');
    }
  });
});

Produces this logs:

window:load
onLoad

Desired behavior:

the onLoadBefore callbacks are not called, this logs are missing:

window:before:load
onBeforeLoad

Test code to reproduce

see example above

Versions

Cypress version: 4.5.0
Browser: Chrome 83
OS: Windows 10 Enterprise, Version 1709

[jennifer-shehane]

I'm not seeing this behavior in 4.10.0 (or 4.5.0).

Perhaps this is relevant to the application you are testing? Can you provide a fully reproducible example?

[delomer]

You are right, my app uses a service-worker and i think if the app is loaded from cache no onLoadBefore event is firing!
When i cancel all already runnig registrations before the test is running the onLoadBefore event is firing.

My updated spec now looks like this and every thing works like expected:

describe('test', () => {
  beforeEach(() => {
   // remove already running service-worker registrations
    if (window.navigator && navigator.serviceWorker) {
      navigator.serviceWorker.getRegistrations().then(registrations => {
        registrations.forEach(registration => {
          registration.unregister();
        });
      });
    }
  });

  it('onload', function() {
    cy.on('window:before:load', e => {
      console.log('window:before:load');
    });

    cy.on('window:load', e => {
      console.log('window:load');
    });

    cy.visit('/', {
      onBeforeLoad(win) {
        console.log('onBeforeLoad');
        // prevent new service-worker registrations
        // https://glebbahmutov.com/blog/cypress-tips-and-tricks/#disable-serviceworker
        delete win.navigator.__proto__.serviceWorker;
      },
      onLoad(win) {
        console.log('onLoad');
      }
    });
  });
});

[jennifer-shehane]

See #702