A Complete Tech Guide For Frontend Job Interview #1

Overview

This guide is designed to provide a structured approach to frontend job interview preparation. It covers a range of topics, from browser and internet fundamentals to asynchronous programming, offering a comprehensive overview of essential knowledge areas. The content is organized to allow for focused study and quick reference.

Interview Rounds

This guide categorizes common interview questions by topic:

Browser and Internet Related

This section focuses on fundamental concepts related to how browsers and the internet work. Key areas include:

• URL Processing: Understanding the steps involved when a URL is entered into a browser.
• HTTP Request and Response:
  • HTTP status codes and their classifications.
  • HTTP cookies: Domain matching, weaknesses, HttpOnly and Secure attributes, and security considerations.
  • SessionID with cookies: Authentication mechanisms and vulnerability mitigation.
  • Cookies vs. localStorage: Use cases and differences.
  • HTTP cache: Headers like Pragma, Cache-Control, Etag, Last-Modified, Expires, and the distinction between no-cache and no-store.
  • HTTP vs. HTTPS: TLS handshake process.
  • CORS: Causes, prevention, and Access-Control- headers.

References:

• MDN Web Docs on HTTP cache
• IETF Documents on HTTP/1.1 RFC - Caches
• CORS series articles by Huli (Mandarin)
• RFC on HTTP over TLS

Browser Rendering

This topic explores the Critical Rendering Path, including:

• Styling Stage: Building the render tree from the DOM and CSSOM trees. Understanding the impact of display: none vs. visibility: hidden.
• Layout Stage: Transforming relative positions to absolute geometry (box model). Understanding margin collapse and solutions.
• Paint Stage: Painting objects into layers and optimizing CSS animations for performance.

References:

• CSS-Tricks on collapsing margins
• CSS-Tricks on rules of margin collapse

Asynchronous

This section covers asynchronous programming concepts, including:

• RESTful APIs: Understanding RESTful API objects and their use cases.
• GET vs. POST Security: Analyzing potential security vulnerabilities when using GET requests for action queries.
• Promise/Async Await Concurrency Limiting: Implementing a function to limit concurrent API calls using Promises or Async/Await.

References:

• StackOverflow on GET vs. POST security
• Article on HTTP POST vs GET security in REST APIs

Key Takeaways

• A solid understanding of browser and internet fundamentals is crucial for frontend interviews.
• Deep knowledge of HTTP protocols, caching mechanisms, and security considerations is essential.
• Understanding the browser rendering process and optimizing performance are critical skills.
• Proficiency in asynchronous programming and API design is expected.
• Continuous learning and staying updated with industry best practices are vital for success.