Coupon applying and calculation library

• This is an extracted code snippet from the project built with ReactJS & NextJS

Flow

• User receives a URL in the format of https://example.com/promote?coupon_code=eMjeTahF&discount_rate=20
• After the user clicks on the link, function checkCouponValidation checks if the coupon is redeemed, and if the user is authorized to use the coupon
• In case the coupon is valid, function calculateDiscountRate calculates the actual discount that the user has received
• New subscription plans with applied discount are displayed on the UI

Demo