Node JS Test Suite that processes an array as an argument

I am writing a Node JS Test Suite that contains six tests. In each test I am passing a variable brand that equals an argument allowing me to pass in a cookie, it looks like this:

const Nightmare = require('nightmare')
const path = require('path')

const nightmare = Nightmare({ show: true })

var someTest = function(brand){
var brand = process.argv[2]

  nightmare
    .viewport(1300, 900)
    .cookies.clear()
    .cookies.set('brand', brand)
    .wait('#auth-email')
    .refresh()
    .wait('#auth-email')
    .screenshot(path.join(__dirname, new Date().getTime() + "3.png"))
    .wait(2000)
    .click('form[name=loginForm] [type=submit]')
    .wait(2000)
    .cookies.clear()
    .end()
    .then((res) => console.log('Successful'))
    .catch((err) => console.error('Errror!'))
}

module.exports = someTest

I have a index.js file that runs all six of the tests when I execute it in my terminal using the command: node index.js brand(cookie), the index.js file looks like this:

someTest = require('./someTest.js')

someTest(process.argv[2]);

someTest2 = require('./someTest2.js')

someTest2(process.argv[2]);

In this index.js file I would like to be able to run an array of brands(cookies) instead of stating it in the command line like: node index.js brand(cookie), to look something like this:

var brand = ['cookie1', 'cookie2']

someTest = require('./someTest.js')

someTest(process.argv[2]);

someTest2 = require('./someTest2.js')

someTest2(process.argv[2]);

However, I am not sure how to process an array as an argument instead. Node is new to me and I am still learning, any insight is much appreciate. Thank you for the help :D