[CS Technical Interview 7] JavaScript That Makes Sense

🥲 Getting a developer job, coding tests weren't the end.

As a non-major, when I first prepared for developer employment, I was obsessed only with algorithms and coding tests. I gained some confidence and passed most coding tests. However, I kept failing at the next hurdle, technical interviews.
What was the problem? It was the lack of CS (Computer Science) knowledge. In interviews, CS fundamentals were considered much more important than algorithms.

🗣 For actual interviews, 'speaking practice' was important.

Even after filling in my CS fundamentals, interviews were still not easy. In an interview at a certain company, I was asked about floating-point numbers. It was content I thought I had read and understood multiple times in books, but I couldn't utter a single word. That's when I realized it. Passive learning through simply reading and understanding cannot provide answers in real situations.

To succeed in interviews, you need not only to accumulate a lot of knowledge but also the ability to explain this knowledge. This 'ability to explain' can only be developed through practice of organizing concepts into just a few sentences and speaking them out loud. Through this process, you can also discover what you didn't know precisely. Without sufficient practice, you'll encounter the following problems.

1. Conceptual Confusion Type

❓Interviewer What are the characteristics of object-oriented programming?
💬 Candidate The SOLID principles. First, S is..(omitted)...

This is a case of confusing similar concepts.
SOLID is an OOP design principle, and the characteristics of object-oriented programming are abstraction, encapsulation, inheritance, and polymorphism.
The moment you mix up related concepts, the interviewer judges that 'your fundamentals are shaky.'
It's not just a simple mistake, but rather it's read as a signal that your conceptual framework is not solid.

2. Lack of Specificity Type

❓Interviewer What are the characteristics of TCP?
💬 Candidate It's a protocol that guarantees reliability.
❓ Interviewer What are the mechanisms that guarantee reliability?
💬 Candidate Uh... well... it makes transmission secure... like that...

This is a case where you only know the What, but are missing the How/Why.
You only know the superficial answers and aren't prepared to explain the underlying principles.
TCP establishes communication through connection (3-way handshake), ensures reliability through RDT (sequence numbers, ACK, retransmission, etc.), and maintains quality through flow control and congestion control.
These concepts need to be connected as one coherent flow in your mind. Without organizing concepts concretely, you cannot prepare for follow-up questions.

3. Getting tongue-tied with basic questions

❓Interviewer What is HTTP?
💬 Candidate Um... it's for sending and receiving data on the web... something like that...?

It's such a familiar concept, but when asked to explain it in one sentence, the words don't come out easily.
Words like request, response, server, and client come to mind, but they don't flow together into a natural sentence.
This is because we've never practiced explaining from definition to principles in one coherent flow.
This isn't a lack of knowledge, but an absence of structure.

Just knowing is not enough. It only becomes real skill when you can express it in words.

🔥 So I created it. The CS Technical Interview Series That Gets You Talking!

🎯 Recommended for these people

Non-majors · Job seekers · Career changers and others who are preparing for technical interviews and need to be able to organize CS fundamentals verbally

⚡ Lecture Core Kick

💡 Use it like this

💬 Q. The lecture time is short, but will I be able to learn properly?

🖐 Hello! Let me introduce myself! 🙇

I created this course while thinking of my past self, who stayed up all night worrying about fundamentals and felt anxious over every single interview question.

I started as a non-CS major and understand better than anyone the thirst for fundamentals (CS knowledge, programming languages, etc.). Through self-studying countless materials and building my own know-how, I eventually graduated from Seoul National University and now work as a 🧑🏻‍💻 Kakao developer.

Since childhood, I've been more confident than anyone in combining and reconstructing various materials to create 'my own comprehensive study notes.' This course is a secret notebook born from that 'ultimate self-study know-how' and all my passion and philosophy.

🔥 What makes this course special?

• All of my 'know-how' is included: As a non-CS major, I have fully incorporated my experience and know-how of self-studying CS and programming languages and getting hired at a large corporation. I have included in this course all the methods for how to most efficiently understand complex and abstract concepts and make them your own.

• 'Fundamentals' are key in any development field: Whether you're aiming for game development, AI, web/app development, or any other field, basic knowledge of computer science is not optional but essential. This course helps you become a true expert based on solid fundamentals.

• We compete with 'overwhelming quality': I've referenced countless materials including textbooks, famous university lectures, commercial books, and technical interview resources to extract core keywords and reconstruct them in my own unique way. With intuitive diagrams and illustrations, plus easy explanations infused with my practical experience, I promise to make even complex concepts click with that "Ah, now I get it!" moment.

🚀 Introducing the seventh lecture of the Technical Interview Master Roadmap, the [JavaScript] edition.

📕 JavaScript is not a language where knowing just the syntax is enough.

• You know variables but are confused about scope/hoisting/TDZ❓

• Are you stuck on explaining why 'this' varies depending on how it's called❓

• Is it difficult to structurally explain the difference between prototypes and classes❓

• Event Loop·Microtasks·Promise·async/awaitIs it difficult to confidently explain the execution order❓

Understanding the 'operating principles' such as scope, execution context, closures, prototypes, and event loops is what gives you real power in practical work and interviews. This course clearly organizes JavaScript's internal workings through diagram-centered, flow-centered, and practice-centered approaches rather than memorization, providing a course that gives you the experience of "words flowing naturally" in interview settings.

🎯 Through this course, you will be able to clearly answer the following questions.

• What are scope and execution context, and why are they necessary?

  
  

  → Understand why hoisting and TDZ occur through the identifier search/initialization rules determined by lexical environment and execution context.

• How is this binding determined?
  → Summarizes the default/explicit/new binding rules and the differences between call/apply/bind with examples.

• What is a closure and when is it useful?
  → Covers the pros and cons in a balanced way, from encapsulating external state and utilizing in events/callbacks to precautions about memory leaks.

• What's the difference between prototypes and classes?
  → We compare prototype chains, method sharing principles, and the abstraction that class syntax provides through diagrams.

• How does the event loop work?
  → Visualize the call stack, task queue, and event loop, and learn the principles of Promise and async/await.

• What is the DOM and how do you manipulate it?
  → Explains node selection and manipulation, event propagation (capturing/bubbling), and preventDefault/stopPropagation together.

• Why are script loading strategies important?
  → We'll organize the differences between defer·async·type="module", ES modules·dynamic import, and code splitting.

  
  

  
  

📌 At the end of the lecture, a practical interview practice chapter awaits you.

You can also practice answering common interview questions like "Explain execution context in one sentence", "Why do we need closures?", "Explain prototype inheritance with a diagram", "Explain the difference between Promise and async/await in terms of execution order", and "Why is bubbling useful?" in one or two sentences by yourself.

📖 A curriculum packed with only the essentials

This is the table of contents and key keywords you will learn in this course.

If there are any unfamiliar keywords, make sure to master them thoroughly with this opportunity.

✏ Here's what you'll learn

👀 Course Preview

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💡 Curious about other interview preparation courses? Check out the roadmap below :)

🔗 Technical Interview Master Roadmap

Pre-enrollment Reference Information