Skill Gap Roadmap — Frontend Engineering, Backend Engineering, System Design

1. 01

   JavaScript fundamentals refresh

   You flagged JS closures and the event loop as weak areas, so this starts with the prerequisite language foundations needed to answer core interview questions confidently.

   6 topics

   • Variables & Data Typesbeginner
   • Operators & Expressionsbeginner
   • Control Flow & Loopsbeginner
   • Functionsbeginner
   • Scopebeginner
   • Hoistingbeginner
2. 02

   Core JavaScript data handling

   These are the most common follow-up areas for frontend interviews and support cleaner explanations of how JS code behaves in real apps.

   5 topics

   • Objectsbeginner
   • Arrays & Array Methodsbeginner
   • Strings, Numbers & Datesbeginner
   • Destructuring, Spread & Restbeginner
   • Modern Syntax Essentialsbeginner
3. 03

   Advanced functions and closures

   This directly fixes the closures gap while covering the function patterns that interviewers often probe around callbacks and `this` behavior.

   5 topics

   • Closuresintermediate
   • Higher-Order Functions & Callbacksintermediate
   • The this Keywordintermediate
   • bind, call & applyintermediate
   • Arrow Functions & IIFEintermediate
4. 04

   Async JavaScript and the event loop

   Event loop mastery is essential for frontend interviews, and this section builds it in the right order from execution context to promises and async I/O.

   5 topics

   • Execution Context & Call Stackintermediate
   • Event Loopintermediate
   • Promisesintermediate
   • async / awaitintermediate
   • Fetch & Network Requestsintermediate
5. 05

   Browser runtime essentials

   These browser primitives are high-signal in frontend interviews and help connect JavaScript behavior to the DOM and user interactions.

   3 topics

   • DOM Fundamentalsbeginner
   • Events & Event Delegationintermediate
   • Browser Storagebeginner
6. 06

   React fundamentals and hooks

   You already know React, so this focuses on the React concepts most likely to be tested for correctness, state flow, and hook usage.

   9 topics

   • JSX & Componentsbeginner
   • Props & Statebeginner
   • Events & Formsbeginner
   • Conditional Rendering & Listsbeginner
   • useState & useEffectintermediate
   • useRef & DOM Accessintermediate
7. 07

   React state, rendering, and production patterns

   This consolidates the deeper React interview topics around rendering behavior, architecture, and reliability without duplicating basic hook coverage.

   10 topics

   • Render & Commit Phasesadvanced
   • Reconciliation & Virtual DOMadvanced
   • Fiber & Concurrent Reactadvanced
   • State Architectureintermediate
   • External Stores (Zustand / Redux)intermediate
   • Server State (TanStack Query)intermediate
8. 08

   Frontend performance and tooling

   These topics help you explain optimization tradeoffs and production readiness, which are common differentiators in mid-level frontend interviews.

   7 topics

   • Memory Management & Garbage Collectionadvanced
   • Debounce & Throttleintermediate
   • Lazy Loading & Code Splittingintermediate
   • Rendering Performanceadvanced
   • Debuggingintermediate
   • Testing Fundamentalsintermediate
9. 09

   TypeScript for frontend interviews

   Since you already know TypeScript, this section reinforces the parts that most often matter in interview code and React-heavy discussion.

   7 topics

   • TypeScript Fundamentalsbeginner
   • Typing Functions & Objectsbeginner
   • Unions & Narrowingintermediate
   • Genericsintermediate
   • Utility Typesintermediate
   • tsconfig & Declarationsintermediate
10. 10

    Frontend system design foundations

    System design should come after the language and React refresh so you can frame tradeoffs clearly before moving into case studies.

    20 topics

    • Scalability Fundamentalsintermediate
    • Back-of-Envelope Estimationintermediate
    • CAP & Consistency Modelsadvanced
    • The Interview Frameworkintermediate
    • DNS, CDN & Edgeintermediate
    • Load Balancingintermediate
11. 11

    Frontend system design case studies

    These are the most relevant practice problems for a frontend-focused interview loop and let you apply the foundations in realistic product scenarios.

    10 topics

    • Design an Autocompleteadvanced
    • Design an Infinite Feedadvanced
    • Design a Design Systemadvanced
    • Design a Collaborative Editor (Client)advanced
    • Frontend Observabilityadvanced
    • Design a URL Shortenerintermediate
12. 12

    Rust Basics for Backend Interviews

    Added on request: "add a section on Rust basics for backend interviews"

    6 topics

    • Rust Syntax and Core Data Typesbeginner
    • Ownership, Borrowing, and Lifetimesintermediate
    • Error Handling in Backend Servicesintermediate
    • Traits, Generics, and Interfacesintermediate
    • Concurrency and Async in Rustadvanced
    • Building Simple Rust Web Servicesintermediate

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