Roadmap

JavaScript fundamentals

• Closures, scope, hoisting, `this` binding
• Prototypal inheritance, constructor functions
• Event loop, call stack
• Implement polyfills for `map`, `filter`, `reduce`, `bind`, `call`, `apply`

Forms & Validation

• Conctrolled vs uncontrolled components
• Form validation patterns, custom validation
• File uploads, multi-step forms
• Build a complex form system with nested validation

Mastering Async

• Promises, async/await, error handling patterns
• Promise combinator methods (`all`, `race`, `allSettled`, `any`)
• Implement Promise from scratch
• Debouncing, throttling, req cancellation
• Build async utilities (queue systemns, rate limiters, retry logic)

DOM, Lodash & Practical JS

• Event delegation, bubbling, capturing
• Virtual DOM concepts (diffing, reconciliation)
• Implement lodash functions: `debounce`, `throttle`, `deepClone`, `get`, `set`, `chunk`, `groupBy`, `flatten`

React

• `useState`, `useEffect`, `useReducer`... understanding
• Custom hook patterns
• Build some custom hooks from scratch

State Management & Architecture

• Context API patterns & limitations
• Redux fundamentals

System Design & Algorithms (frontend)

• Components design patterns
• Infinite scroll, autocomplete...
• Performance optimisation (lazy loading)

Data Structures & Algorithms (Python)

• Solve LC daily (trees, graphs, bfs, dfs, stacks, queues, tries, DP...)