Cypress.Chainable incorectly wrapping any as JQuery<any> in typedef

[MCFreddie777]

Current behavior

When returning any from cypress chainable both following methods return types are Cypress.Chainable<JQuery<any>> which is incorrect.

 foo() {
        return cy.get('body').then((_) => {
            return {} as any;
        });
    }

 foo() {
        return cy.request('/').then(response => {
            return response.body.bar;
        });
    }

Desired behavior

Tested on Cypress 6.9.1, it correctly return Cypress.Chainable<any>.

Versions

Tested on 6.9.1 - working as expected, 7.3.0, 7.4.0 - incorrect types

[jennifer-shehane]

Maybe related to #15869 or #15624 We're open to a pull request to fix the types.

[sainthkh]

Sorry for the late reply.

I checked the code and found out the it failed because the type of response.body is any. It's been raised at #9109 and solved at #16743.

With it solved and you can write code like below:

interface ResBody {
  x: number
  y: string
}

cy.request<ResBody>({
  url: 'http://goooooogle.com',
  body: {}
}).then((resp) => {
  return resp.body.y
}).then(a => {
  a // => string
})

Meanwhile, you can manually cast the type like below:

cy.request({
  url: 'http://goooooogle.com',
  body: {}
}).then((resp) => {
  return resp.body.y as string
}).then(a => {
  a // => string
})

I thought about ways to revert the behavior, but it seems that it's impossible because any extends HTMLElement is true. And we cannot put S extends any on the top, then it'll handle all the definitions.

[MCFreddie777]

@sainthkh It's totally okay. Yes I know cy.request is proposed to be generic, but it is not at the moment.

If you look at the first example, it does not relate to the cy.request only, but to the Chainable (.then()) in general.
It casts implicit and explicit any as jQuery<any> which is unwanted behaviour.

If you explicitly specify return type of fn, it works okay.

But, with other types - it does not.
Here's example with string without explicit function return typedef, it has correct type.

[sainthkh]

At first, I thought it was impossible because it's how any works. But I found a way.