cypress.io - wait for an lazy loaded js-file

Question

we want to test a webpage that does an ajax-request after clicking a button.

We are able to wait for the response of this ajax-request by defining a cy.route()

cy.server()
cy.route("POST", '/exampleAjax').as('exampleAjax')
cy.get('.button').click()
cy.wait('@exampleAjax')

Within the onComplete-Block of the ajax-Response we create an script-Tag and insert it:

new Ajax.Request( "exampleAjax", {
    method: "post",
    parameters: {'data-id': dataID},
    onComplete: function(transport) {
        var snode = document.createElement('script');  
        snode.setAttribute('type','text/javascript');                  
        snode.setAttribute('src','/some.js');
        document.getElementsByTagName('head')[0].appendChild(snode); 
    }
});

Now we want to wait for some.js to be loaded and tried

cy.route("GET", '/some.js').as('some_js')
cy.wait('@some_js')

But this does not work. How can we achieve this?

Answer 1

This is not possible with cypress currently. Cypress team is working on network stubbing. Take a look at this issue.

Answer 2

While we are still waiting for the feature request linked by Art713 we found a workaround for us:

We let cypress check for a global var / function that is defined within the lazy-loaded js-file:

cy.window().its('<any global var / function>')

In our case we also increased the defaultCommandTimeout within cypress.json in order to avoid a timeout after 4 seconds

{
  "defaultCommandTimeout": 10000
}