Strategy & Factory Patterns: Payment & Courier Code
php
dev.to
Almost every e-commerce or SaaS backend starts with a single payment gateway and a single shipping carrier. A developer writes a quick if ($gateway === 'stripe') check inside CheckoutService, ships the feature, and moves on. Six months later, the business expands: now you need PayPal, JazzCash, Safepay, and Cash on Delivery (COD) for payments, plus DHL, TCS, and Leopards for courier booking. Suddenly, CheckoutService is a 900-line tangle of nested if/else and switch blocks where a bug in one cou