Let’s go over how to set the Firefox profile for WebDriverJS (Selenium for Node.js).

Prerequisites

Install Firefox browser with Homebrew:

brew cask install firefox

Install geckodriver:

brew install geckodriver

Building your driver

Now you want to build your driver. See how it’s done here.

Firefox options

Before instantiating the driver, you want to set the profile in Firefox options:

const firefox = require('selenium-webdriver/firefox');
const options = new firefox.Options();
// replace `/path/to/profile`
options.setProfile('/path/to/profile');

Unlike ChromeDriver, the profile must be valid otherwise the driver will fail to build. To create and manage Firefox profiles, see the official documentation.

Update the builder so WebDriverJS launches Firefox based on the specified profile:

builder.forBrowser('firefox');
builder.setFirefoxOptions(options);

To confirm the profile is correct, you can check the path if you go to about:support:

const driver = builder.build();
driver.get('about:support');