Ensure a seamless, intuitive, and controlled experience when applying coupon codes in the cart drawer by:

  • Clearly displaying applied coupons.
  • Preventing multiple or duplicate coupon entries.
  • Providing users with the option to remove applied coupons.
  • Maintaining synchronization with backend/cart state.

Why Is Showing Applied Coupons and Preventing Reapplication Important?

Avoid User Confusion:

Reapplying or overriding active coupons can mislead users or result in unexpected cart totals.

Prevent Redundant Requests:

Unnecessary backend calls for re-applying the same or conflicting discount codes.

Provide Clear User Feedback:

Transparency builds trust; users should always see the active promotions clearly.

Support UX Consistency:

Standardize coupon behavior across the platform (drawer, checkout, etc.).

Implementation Plan

1. Store and Track the Applied Coupon

  • Leverage the cart.discountApplications property (e.g., from Shopify, custom backend, or session-based cart logic).
  • Upon cart load, check if a coupon is already applied.
JS
if (cart.discountApplications.length > 0) {
displayCoupon(cart.discountApplications[0].code); // Display applied code
disableCouponInput(); // Disable input to prevent reentry
}

2. Display the Active Coupon in Cart Drawer

  • Show the applied coupon code prominently.
  • Include a “Remove” or “Clear” button next to the coupon to give users control.
  • Style the display using a pill or badge UI for clarity.

Yaml

Coupon Applied: SUMMER20 ✕

3. Prevent Duplicate Entry

  • If a coupon exists, disable the coupon input field or form submission.
  • Optionally show a tooltip or small message like: “Coupon already applied. Remove it to apply another.”

4. Remove Coupon Functionality

  • Allow the user to remove the applied coupon, which:
    • Clears cart.discountApplications.
    • Re-enables the coupon input field.
    • Optionally notifies the user (e.g., “Coupon removed” toast).

5. Handle Error Cases Gracefully

  • If a user attempts to apply a coupon while one is already applied, show an error or tooltip: “Only one coupon can be used per order. Remove the current coupon to apply for a new one.”
  • If the coupon code is invalid, show specific messaging received from the backend (e.g., “Code expired” or “Not applicable to your cart.”).

Backend/API Considerations

  • Ensure the backend API checks for:
    • Single coupon constraint.
    • Coupon code validity.
    • Proper response with error messages or applied status.