Frontend 0 → PRO

TS config (tsconfig), strict mode

Types vs interfaces, unions/intersections

Generics and utility types

Typing API contracts (DTOs)

Migration JS → TS strategy

Pick one: React / Vue / Angular (core concepts)

Routing & code splitting

State management patterns

Data fetching (caching, retries)

SSR/SSG overview (Next/Nuxt/etc.)

Component design & composition

Design systems basics

Forms at scale (validation, UX)

Error boundaries and resilience

Feature flags (overview)

Unit testing (Vitest/Jest)

Component testing (Testing Library)

E2E (Playwright/Cypress overview)

Mocking APIs, fixtures

CI tests + coverage basics

Web performance basics (LCP/CLS/INP overview)

Bundle analysis and optimization

Caching strategy (HTTP cache, SW overview)

Security: XSS/CSRF/CSP overview

Deploy checklist (env, errors, monitoring)