Add query params to ALL requests in Cypress

Question

I have a lot of Cypress tests that all need to have the same query param as I render the page slightly differently while running integration tests.

Currently I am adding the query param each time I use cy.visit, like so:

    cy.visit('/path/to/page', {
      qs: {
        myParam: true
      }
    });

However I have a lot of test files, so if possible I would like to apply this param by default when visiting a page. I can't find an option in the docs to do this. So other than creating a custom wrapper, is it possible to enable this by default. Ideally I would do it from defineConfig, or something similar. Like:

defineConfig({
  visit: {
    qs: {
      myParam: true
    }
  }
});

Answer 1

You can simply use Cypress's API to overwrite the visit command to automatically add a query string parameter

In the support.ts file you can do something like this

Cypress.Commands.overwrite('visit', (orig, url, options) => {
  // checks to make sure we don't break setting options when overwriting
  if (!options) {
    options = {};
  }

  if (!options.qs) {
    options.qs = {};
  }

  options.qs.myParam = true;

  return orig(url, options);
});

I verified this works, but it appears there's an issue logged with Cypress about a type issue when overwriting visit (https://github.com/cypress-io/cypress/issues/25540), so it may report type issues. You may need to ts-ignore some lines until the issue is resolved.

Here is some more information on overwriting existing commands: https://docs.cypress.io/api/cypress-api/custom-commands#Overwrite-Existing-Commands