script.js

var products = ["TITLE1", "TITLE2", "TITLE3"];
$( ".btn-coupon" ).click(function(e) {
  $( ".cart-line-items-v2 li" ).each(function() {
        var productTitle = $(this).find(".line-title").text();
        console.log("Product Title: " + productTitle);
        for (i = 0; i < products.length; i++) {
             if (productTitle == products[i]) {
               e.preventDefault;
               break;
             }
         }
    });
});