Add new post about Swift refactor

content/posts/series/swift-code-refactor/2/index.md

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+---
+title: '#2 Swift code refactor in action - price $$$'
+date: 2024-12-03
+tags: ['Swift', 'Refactoring']
+series: "Swift code refactor in action"
+cover: 
+  image: 'images/cover.png'
+  alt: '#2 Swift code refactor in action - price $$$'
+---
+
+Swift code refactor in action 👨🏻‍💻
+
+Today, let’s talk about refactoring for clarity, maintainability, and scalability!
+
+This time, the scenario is calculating the final price depending on the price and membership status.
+
+This initial code has a few code smells:
+- 1️⃣ nested ifs - impacts general readability, making the code hard to understand,
+- 2️⃣ duplicated conditions - "price > 100" which violates the Don’t Repeat Yourself principle,
+- 3️⃣ lack of scalability - not possible to easily add a new discount, it’d require to rework everything.
+
+Checkout the gif or the post on my website to see how I solve these code smells and make the code cool, clean and scalable!
+
+Gif ⤵️
+
+![Refactoring](images/refactoring.gif)
+
+Code ⤵️
+
+#1
+```swift
+func calculatePrice_v1(price: Double, isMember: Bool) -> Double {
+    if isMember {
+        if price > 100 {
+            return price * 0.9
+        } else {
+            return price * 0.95
+        }
+    } else {
+        if price > 100 {
+            return price * 0.95
+        } else {
+            return price
+        }
+    }
+}
+```
+
+#2
+```swift
+func calculatePrice_v2(price: Double, isMember: Bool) -> Double {
+    isMember ? priceForMember(price: price) : priceForNonMember(price: price)
+}
+
+func priceForMember(price: Double) -> Double {
+    price > 100 ? price * 0.9 : price * 0.95
+}
+
+func priceForNonMember(price: Double) -> Double {
+    price > 100 ? price * 0.95 : price
+}
+```
+
+#3
+```swift
+func calculatePrice_v3(price: Double, isMember: Bool) -> Double {
+    apply(discount: isMember ? .member : .regular, to: price)
+}
+
+func apply(discount: Discount, to price: Double) -> Double {
+    price > discount.threshold ?
+        price * discount.premiumRate : price * discount.standardRate
+}
+
+struct Discount {
+    let threshold: Double
+    let standardRate: Double
+    let premiumRate: Double
+
+    static let member = Discount(threshold: 100, standardRate: 0.95, premiumRate: 0.9)
+    static let regular = Discount(threshold: 100, standardRate: 1, premiumRate: 0.95)
+}
+```
+
+{{< footer >}}