Shopify Checkout.liquid javascript helper to parse product list.

shopify_checkout.js

console.clear()

var product_rows = document.querySelectorAll('.sidebar  .product-table .product')
var products_main = []
var products_accs = []

var product_main_strings = ["Regex Title"]
var product_accs_strings = ["Regex Title2", "Regex Title3"]

var matchProducts = function(i) { if ( this.product.name.match(i) ) this.array.push(this.product) }

String.prototype.processImage =  function() {
  return this.replace(/_small(?=\.\w+\?)/, '_large')
}


product_rows.forEach(function(row) {
  var product = { 
    name: row.querySelector('.product__description__name').textContent, 
    variant: row.querySelector('.product__description__variant').textContent, 
    image: row.querySelector('.product-thumbnail__image').src.processImage()
   }

  product_main_strings.map(matchProducts, { array: products_main, product: product })
  product_accs_strings.map(matchProducts, { array: products_accs, product: product })
})

console.log(products_main, products_main[0].image)
console.log(products_accs)

// Update Image
document.querySelector('.featured-image').style.backgroundImage = `url(${products_main[0].image}`