Problem with TypeScript signature

[mistic100]

Hi,

I think there is an error in the return type of the function.

Because

If you return a truthy value, it becomes the subject for the next command.

the function actually returns Chainable<ReturnType> but currently it is declared as Chainable<Subject>

declare namespace Cypress {
  interface Chainable<Subject = any> {
    waitUntil<ReturnType = any>(
      checkFunction: (
        subject: Subject | undefined
      ) => ReturnType | Chainable<ReturnType> | Promise<ReturnType>,
      options?: WaitUntilOptions<Subject>
    ): Chainable<Subject>
  }
}

thanks.

[NoriSte]

Can you please elaborate more, please? With some eventual IDE's screenshots and/or shiki twoslash reported type? The Chainable<Subject> comes from Cypress and can't be changed

[mistic100]

Your function returns a Chainable object whose value is the one returned by checkFunction and whose type is ReturnType.

Currently the function is typed to return Chainable<Subject> but it should be Chainable<ReturnType>, which is what it actually returns here https://github.com/NoriSte/cypress-wait-until/blob/master/src/index.js#L57 (the initial subject is not returned).

Take this example (written from memory) :

// assume a task "myTask" which return the following type
type MyTaskReturn {
  uid: string;
}

cy.get('#input1')
   // get value of input1
   .its('value')
   // execute the task to make somthing with the value
   .waitUntil((value) => cy.task<MyTaskReturn>('myTask', value))
   // write the task result in another input
   .then(result=> {
      cy.get('#input2').type(result.uid); // ERROR: "uid" is not defined on type string
   });

Here result is typed string because it is the type of the subject passed to waitUntil but it is, in fact, the retuned value of my task, so MyTaskReturn.

I don't see how this couldn't be changed.

---

I can provide tomorrow a real example, but it is basically this.

[mistic100]

Real world example : here waitUntil is not chained from another query, as such the result value is not typed at all.

cy.waitUntil(() => {
      return cy.task<string[]>('listFiles', {
          dir: Cypress.config('downloadsFolder'),
          name: name,
      });
  })
  .then((results) => {
     if (results.length === 1) { // ERROR 'results' is possibly undefined
         ....
     }
  });

(the implementation of waitUntil garantees that the result cannot be undefined)

If I force the type with .then((results: string[]) => { it compiltes.

And If I edit your d.ts to return Chainable<ReturnType> it works too.

[NoriSte]

🎉 This issue has been resolved in version 3.0.0 🎉

The release is available on:

• GitHub release
• npm package (@latest dist-tag)

Your semantic-release bot 📦🚀

[NoriSte]

You were right, thank you so much for reporting it ❤️

[NoriSte]

@all-contributors please add @mistic100 for bug

[allcontributors]

@NoriSte

I've put up a pull request to add @mistic100! 🎉