`UnexpectedAlertOpenError` in Selenium Webdriver on Node.js is present even after dismissing the alert

Question

I am using Cucumber.js and Selenium Webdriver JS in a Node.js environment, using Firefox as my browser.

I am trying to test a page that shows an alert on load. I have created a Cucumber step to dismiss the alert box which appears to work (visibly, the alert disappears) but I still get the error:

UnexpectedAlertOpenError: Dismissed user prompt dialog: Some alert text...

I have tried many different ways of getting around this but have had no success.

I have tried:

Setting an option when I build the browser:

let options = new firefox.Options();
options.setAlertBehavior(UserPromptHandeler, 'dismiss');
this.driver = new Builder()
    .forBrowser('firefox')
    .setFirefoxOptions(options)
    .build();

Dismissing it in a Cucumber step:

When('I dismiss the alert', async function() {
    this.driver.switchTo().alert().then((alert) => alert.dismiss());
});

And this way (as per Selenium docs):

When('I dismiss the alert', async function() {
    await this.driver.wait(until.alertIsPresent());
    let alert = await this.driver.switchTo().alert();
    await alert.dismiss();
});

I've also tried waiting before dismissing:

When('I dismiss the alert', async function() {
    await this.driver.manage().setTimeouts({ implicit: 3000 });
    this.driver.switchTo().alert().then((alert) => alert.dismiss());
});

And

When('I dismiss the alert', async function() {
    await this.driver.sleep(3000);
    this.driver.switchTo().alert().then((alert) => alert.dismiss());
});

But no matter what I do I always get same error as above on the "When I dismiss the alert" step.

Would anyone know what I need to do to solve this error?

My full code:

const { When, Then, Given } = require('@cucumber/cucumber');
const { Builder, By, until, Key } = require('selenium-webdriver');
const { Options } = require('selenium-webdriver/firefox');
const firefox = require('selenium-webdriver/firefox');
const { UserPromptHandeler } = require('selenium-webdriver/lib/capabilities');

Given('I am on the branch locator page', async function () {
    let options = new firefox.Options();
        //options.setAlertBehavior(UserPromptHandeler, 'dismiss');
    this.driver = new Builder()
        .forBrowser('firefox')
        .setFirefoxOptions(options)
        .build();
    
    this.driver.wait(until.elementLocated(By.tagName('h1')));

    await this.driver.get('https://www.awebsite.com');    
});

 When('I dismiss the alert', async function() {
    await this.driver.sleep(3000);
    //await this.driver.manage().setTimeouts({ implicit: 3000 });
    this.driver.switchTo().alert().then((alert) => alert.dismiss());
    // await this.driver.wait(until.alertIsPresent());
    // let alert = await this.driver.switchTo().alert();
    // await alert.dismiss();
});

Then('I click the radio button', async function() {
    await this.driver.findElement(By.id('option2')).click();
});

Answer 1

I got this working by looking through the capabilities.js file in the selenium-webdriver folder within node-modules.

I can set it to dismiss alerts automatically but setting the option:

options.setAlertBehavior('dismiss');

Eg:

let options = new firefox.Options();
    options.setPreference('geo.enabled', false);
    options.setAlertBehavior('dismiss');

const driver = new Builder()
    .forBrowser('firefox')
    .setFirefoxOptions(options)
    .build();