Chapter 18 — Yakuniy Loyihalar

Handbook davomida o'rgangan barcha TypeScript bilimlarini birlashtiruvchi progressiv loyihalar.

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18.1 🟢 Level 1-2: Typed Todo List va Shape Calculator

Loyiha 1 — To'liq Tiplangan Todo List

Talablar: Todo interfeysi, add/remove/toggle funksiyalari, barchasi to'g'ri tiplangan. Konseptlar: interfeyslar, massivlar, funksiya tiplari.

Loyiha 2 — Shape Area Calculator

Talablar: Diskriminatsiyalangan union (Circle, Square, Rectangle), exhaustiveness checking bilan getArea funksiyasi. Konseptlar: diskriminatsiyalangan union, switch, never.

18.2 🟡 Level 3-4: Generic API Client va State Machine

Loyiha 3 — Generic API Client

Talablar: fetchData<T>(url: string): Promise<T> generic funksiyasi, ApiResponse<T> interfeysi bilan. Konseptlar: generics, utility types (Partial update funksiyalari uchun).

Loyiha 4 — UI State Machine

Talablar: "idle" | "loading" | "success" | "error" holatlariga ega diskriminatsiyalangan union, har biriga mos komponent render mantig'i (konseptual, UI'siz). Konseptlar: diskriminatsiyalangan union, type narrowing.

18.3 🔴 Level 5-6: Form Validation Library va Mini ORM Types

Loyiha 5 — Type-Safe Form Validation

Talablar: Generic Validator<T> interfeysi, turli maydon turlari (string, number, email) uchun validatorlar, xatolarni to'plovchi tizim. Konseptlar: generics, utility types, function types.

Loyiha 6 — Mini ORM Tip Tizimi

Talablar: User, Product kabi "model" interfeyslaridan, Partial/Pick/Omit yordamida CreateUserInput, UpdateUserInput kabi turli maqsadli turlarni avtomatik hosil qilish. Konseptlar: utility types, mapped types.

18.4 🟣 Final Project: To'liq Tiplangan Mini E-commerce Backend Types

Talablar

• To'liq domain modeli: Product, Order, User, CartItem interfeyslari (PART 3, 7)
• Diskriminatsiyalangan union orqali OrderStatus (pending/shipped/delivered/cancelled) va har biriga mos qo'shimcha ma'lumot (PART 14)
• Generic Repository<T> interfeysi (findById, create, update, delete metodlari) (PART 11)
• Utility types yordamida CreateProductInput, UpdateProductInput kabi turlar (PART 12)
• Type-safe event system: type AppEvent = { type: "order.created"; orderId: string } | ... (PART 14)

📝 Practice Exercises

🟣 Exercise 1 — Final Challenge

Task: Yuqoridagi Final Project talablarini to'liq amalga oshiring — barcha interfeyslar, diskriminatsiyalangan union'lar, generic Repository va utility type'lar bilan (implementatsiyasiz, faqat tip darajasida).

🐛 Debugging Challenge (Loyiha Darajasida)

Stsenariy: Repository<T> interfeysini amalga oshirganingizda, findById metodi T | undefined qaytarishi kerak (chunki element topilmasligi mumkin), lekin siz uni T deb yozgansiz va endi barcha joylarda "obyekt undefined bo'lishi mumkin" degan runtime xatolarga duch kelmoqdasiz.

Your Task: Bu muammoni qanday tuzatish kerak?

<details> <summary>Solution</summary> ```typescript interface Repository<T> { findById(id: string): T | undefined; // to'g'ri — topilmasligi mumkinligini aks ettiradi create(data: Omit<T, "id">): T; update(id: string, data: Partial<T>): T | undefined; delete(id: string): boolean; } ``` Bu — `findById`ni chaqirgan har bir joyda, TypeScript dasturchini natijani ishlatishdan oldin `undefined`ligini tekshirishga "majburlaydi", bu esa PART 1'dagi `strictNullChecks` tamoyilining amaliy qo'llanilishi. </details>

📌 Chapter Summary

Capstone loyihalar — oddiy tiplangan Todo List'dan to'liq, generic va diskriminatsiyalangan union'larga asoslangan e-commerce backend tip tizimigacha, handbookda o'rgangan barcha TypeScript tushunchalarini (asosiy tiplar, interfeyslar, generiklar, utility types, advanced types, diskriminatsiyalangan union'lar) birlashtiradi.

🎯 Key Takeaways

• Har bir loyiha oldingi bilimlar ustiga quriladi
• Generic Repository<T> — real backend arxitekturasining asosiy patternlaridan biri
• Diskriminatsiyalangan union — event va status tizimlari uchun standart yechim
• Funksiya imzolari — haqiqiy xatti-harakatni (masalan undefined bo'lish ehtimolini) to'g'ri aks ettirishi kerak

⚡ Quick Cheat Sheet

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01🟢 Todo List, Shape Calculator → interfeyslar, diskriminatsiyalangan union
02🟡 API Client, State Machine → generics, narrowing
03🔴 Form Validation, Mini ORM → generics + utility types
04🟣 Final Project → Barcha konseptlar birgalikda

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