promo.js

let code_types = {};

code_types.cart = (promo, products) => {
    let products = productUtils.getProductsByType(products, promo.product_types);
    let total = 0;
    
    products.forEach((item) => {
        total = total + productUtils.getTotal(item, promo.use_contract_price ? account.org.price_contracts[item.format] : 0);
    });

    if (
        total < promo.min_total // total is less than the min_total
    ) {
        // Promo cannot be applied.
        return false;
    }

    return true;
};

code_types.order = (promo, products) => {
    let total = promo.use_contract_price ? cartUtils.getGrandTotal(products) : cartUtils.getSubTotal(products);

    if (
        total < promo.min_total // total is less than the min_total
    ) {
        // Promo cannot be applied.
        return false;
    }

    return true;
};

let testPromoCode = (code, products) => {
    let promo = promoUtils.getPromoByCode(code);
    let future = Date.now() < new Date(promo.start_date).getTime();
    let expired = Date.now() > new Date(promo.end_date).getTime();
    if (
        !products.length || // no products matching the product_types allowed
        !promo.active || // active not true
        future || // start_date in the future
        expired || // end_date in the past
    ) {
        return false;
    }
    return code_types[promo.type](this, promo, cart);
};

promos.json

[{
  "code": "KICKSTARTPW",
  "type": "cart",
  "active": true,
  "start_date": "2015-10-29T17:59:02+0000",
  "end_date": "null",
  "min_total": 3500,
  "product_types": [
    "playaway",
    "recorded_books"
  ],
  "discount_ammount": 0.3,
  "discount_type": "percent",
  "use_contract_price": false,
  "_id": "1234lkj12l34kjljk1l234"
},
{
  "code": "WOOT10Off",
  "type": "order",
  "active": true,
  "start_date": "2015-10-29T17:59:02+0000",
  "end_date": null,
  "min_total": 3500,
  "product_types": null,
  "discount_ammount": 0.1,
  "discount_type": "percent",
  "use_contract_price": false,
  "_id": "1234lkj12l34kjljk1l234"
}]