Adding an if condition to Promise.all

Question

I am trying to do the following:
When I am on the cart page and click the CHECKOUT button, then there are 2 things that can happen:
I am redirected to the checkout page
I am asked sometimes to log in again => this is a bug in the app since I am already logged in but it asks me to log in again for some reason.
I need to write a Playwright test for the checkout process. And in this test, I need to support that buggy behavior since there is no indication it will be resolved any time soon (or whatsoever).

This is what I got so far:

async clickCheckoutBtn() {
    if (this.#isGuest) {
      // redirects to the login page, so we don't have waitForURL like when we are logged in
      await this.#checkoutBtn.click();
    } else {
      // TODO add here somehow to login again if required after clicking the checkout button
      await Promise.all([
        this.page.waitForResponse(
          (response) =>
            response.url().includes('/my-account/addressform') &&
            response.status() === ResponseCode.SUCCESS
        ),
        
        this.#checkoutBtn.click(),
        this.page.waitForURL(/.*\/delivery-address\/add$/),
      ]);
    }
  }

Now, this is what I would like to do:

await page.getByRole('button').click();
    if(await page.getByPlaceholder('login').isVisible()) {
      await loginPage.login(username, password);
    } 
    await page.waitForURL(/.*\/delivery-address\/add$/),  

But in the case when I am redirected to the checkout I also need to waitForResponse of the /my-account/addressform. (so after logging in I need to wait for it, but also after direct redirect to the checkout page, I need to wait for it as well)
So I would like to do this somehow inside the Promise.all, but I don't how to do it.
Can you please help?

Answer 1

Yes you can do something like below using ternary operator.

Promises are future values which can be captured in variables and moved around in code asynchronously.

var p1 = page.getByRole('button').click();
var p2 = (await page.getByPlaceholder('login').isVisible()) ? loginPage.login(username, password) : Promise.resolve() //else empty promise which will resolve immediately
Promise.all([p1, p2]).then(results => {
       await page.waitForURL(/.*\/delivery-address\/add$/)
});

More abstract version of it for general understanding:

var p1 = functionA();
var p2 = condition ? functionB() : Promise.resolve(); // or empty promise
Promise.all([p1, p2]).then(results => {
      // code to handle results
});