I Joined JavaScript Hard Parts Course on Frontend Masters - Here is My Honest Review

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Hello guys, if you are looking for a deep dive course to learn JavaScript in depth then have come to the right place. 

Earlier, I have shared best JavaScript courses, books, and websites and today, I am going to share an awesome online course called “JavaScript Hard Parts v2” from Frontend Masters, one of my favorite place to learn web development and JavaScript.

This course aims to teach you advanced JavaScript topics like callbacks and higher-order functions, closure, asynchronous JavaScript, and object-oriented JavaScript!

Frontend Masters has long been known for its high-quality, in-depth courses on various web development topics, and “JavaScript: The Hard Parts” by Will Sentance of Codesmith is no exception.

In this review, we’ll dive into the content, structure, and overall value of this course to help you determine if it’s worth your time and investment.

By the way, I have an exciting news to share with you, Frontend Masters is offering $100 off their yearly membership during their Knowledge Quest Sale.

This is your chance to access over 200+ premium courses, guided learning paths, and new platform features, all at a fraction of the cost.

Whether you want to master JavaScript, React, or DevOps, now’s the time to join and level up your skills. Don’t miss out — the sale ends on 18th September!

👉 Join today and save $100 on your yearly membership!

Now, coming back to the topic, We will review the course on Instructor expertise and content structure, and find out whether its worth of your time and money or not.

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Instructor Expertise

The instructor of this course, Will Sentance is co-founder and CEO at Codesmith — a software engineering and machine learning company based in Los Angeles, New York, and Oxford.

He is the creator of Icecomm, the most famous developer platform for P2P video and data communication. Before Codesmith, Will was CEO at Ownly and a Software Engineer at Gem.

When it comes to teaching Will has got a an interesting and engaging way to to teach complex concepts. He has got a great voice and you will not fall a sleep while watching his classes.

He also have in-depth knowledge of JavaScript internals and how it works under the hood, which even shows in the preview lesson which you an watch for free.

Course Overview

“JavaScript: The Hard Parts” is designed to take you under the hood of some of the most critical aspects of JavaScript. The course promises to provide a deep understanding of advanced JavaScript concepts like callbacks, higher-order functions, closure, asynchronous JavaScript, and object-oriented JavaScript.

It’s aimed at developers with a basic to intermediate knowledge of JavaScript who want to elevate their understanding to the next level.

Content and Structure

The course is divided into several learning paths and topics, each focusing on fundamental JavaScript principles:

1. JavaScript Principles: Covers the basics of JavaScript execution, functions, and the call stack.
2. Functions & Callbacks: Explores generalized functions, higher-order functions, callbacks, and arrow functions.
3. Closure: Dives into the concept of closure, how it works, and its practical applications.
4. Asynchronous JavaScript: Discusses single-threaded execution, asynchronicity in JavaScript, web APIs, promises, and async/await.
5. Classes & Prototypes: Covers object-oriented programming concepts, including factory functions, prototype chains, the this keyword, and the new keyword.

Each topic is further broken down into detailed lectures, with Will Sentance providing clear explanations, diagrams, and real-world examples to reinforce key concepts.

It’s also very details as you can see from this table of content:

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Closure:

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Asynchronous JavaScript:

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Promises:

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Classes and Prototypes

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You can see that each of the advanced JavaScript topics like callbacks and higher-order functions, closure, asynchronous JavaScript, Promises and object-oriented JavaScript is covered in detail.

Pros

Apart form Frontend Masters impeccable video and audio quality and well structure content, here are few more highlights of this course which makes it worth of your investment.

1. In-Depth Coverage: The course delves deeply into complex JavaScript concepts, providing a thorough understanding of each topic.
2. Clear Explanations: Will Sentance’s teaching style is clear, engaging, and easy to follow, making even challenging concepts more accessible.
3. Real-World Examples: Real-world examples and practical applications help reinforce theoretical knowledge and make it easier to understand how these concepts apply in actual development scenarios.
4. Interactive Exercises: Pair programming exercises and coding challenges encourage hands-on learning and application of the concepts covered in each section.

Here is the link to join this course — “JavaScript: The Hard Parts”

Cons

Nothing is perfect, and there is always room for improvements, here are few things which may cause concern before you join the course.

1. Advanced Material: While the course is valuable for intermediate developers looking to deepen their understanding of JavaScript, some beginners may find the content challenging to grasp without a solid foundation in the language.
2. Intensive Time Commitment: With over six hours of content, the course requires a significant time investment to complete fully.

Conclusion

In short, Yes, “JavaScript: The Hard Parts” on Frontend Masters is a comprehensive and valuable resource for developers looking to master advanced JavaScript concepts like callbacks and higher-order functions, closure, asynchronous JavaScript, Promises and object-oriented JavaScript .

It’s 100% worth it because of its in-depth coverage, clear explanations, and practical examples, the course offers a solid foundation for understanding the inner workings of JavaScript.

If you’re willing to put in the time and effort to tackle the challenging material, this course can undoubtedly help you level up your JavaScript skills and become a more versatile and problem-solving developer.

However, beginners may want to ensure they have a solid understanding of JavaScript basics before diving into this course.

In summary, if you’re serious about advancing your JavaScript knowledge and are ready to tackle the hard parts, this course is undoubtedly worth considering.

All the best with JavaScript learning journey.

If you want to do just one thing, go and join this course on Frontend Masters

Learning the Hard Parts of JS

Take your JavaScript to the next level. Gain an understanding of callbacks, higher-order functions, closure…

bit.ly

Other Frontend Masters Articles you may like to read

• Is the TypeScript course on Frontend Masters worth it? Review
• Is The Node.js course on Frontend Masters worth it? Review
• Is the React.js course on Frontend Masters worth it? Review
• Is Frontend Masters’ “The Last Algorithms Course You’ll Need” worth it? Review
• Top 5 Project-based courses from Frontend Masters to Learn JavaScript Better
• Top 5 Frontend Masters Courses You Can Take in 2024

Thank you for reading this article till the end. If you like this course then please share with your friends and colleagues. If you have any questions or doubts then feel free to ask.

P. S. — If you are keen to level up your frontend skills then joining frontend master can be a great first step as they have awesome courses to learn valuable frontend skills 👉 Join today and save $100 on your yearly membership!

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Top 10 Must-Know Object Oriented Analysis and Design (OOAD) Interview Questions for Senior & Experienced Developers (2026)

Testing Object Oriented analysis and design skill of a candidate is quite common in programming job interviews. Questions like, how do you design a vending machine or a traffic control system are very popular in object-oriented programming language interviews, like Java and C++. Designing a software System requires good experience and knowledge of tools of object-oriented design and analysis.

You should not only be good at OOP fundamentals like Abstraction, Inheritance, Polymorphism, Encapsulation, Coupling, Cohesion, Association, Aggregation, or Composition but also on several crucial object-oriented design principles like SOLID Principles of Object-Oriented Design, which is the building block for writing flexible and maintainable code.

Good knowledge of when to use a class over an interface is also essential for designing a maintainable software or Java application. Now, the questions are how do you develop such skills? You need to practice and practice hard. 

This is why I am sharing some frequently asked object-oriented design questions from Java programming interviews here.

Anyway, Software design has many facets, object-oriented system design is just one of them. Sometimes, you may be asked to design a database for an e-commerce application. Database design is totally different than object-oriented design.

There you need to follow rules of flexible and maintainable designs and Normalization. You need to make sure your tables are in 3rd normal form, and there is a nice balance between duplication of data and the easiness of querying the data.

Btw, this tutorial is about object-oriented system design, and I’ll share questions on that. I’ll write about SQL and database design sometime later to give you more information and some practice questions as well.

Another thing to note is that now there are a couple of excellent courses available online, which can help you with this challenging aspect of coding interviews. I have tried the Grokking System Design Interview and Grokking the Object-Oriented Design Interview courses from Designgurus.io, and I must say they are excellent to prepare well.

These courses are designed by the hiring managers of Google, Facebook, Microsoft, and Amazon. They not only has a set of carefully handpicked case studies, which have been repeatedly asked at the top tech companies but also provide a thorough experience to handle different object-oriented design scenarios.

10 Object-Oriented and Software Design Interview Questions and Problems

Here is my list of frequently asked object-oriented and software design questions from programming job interviews. You will find such kinds of questions not only on biggies like Amazon, Google, Microsoft, and Facebook but also on small startups and service-based companies like Infosys, Wipro, TCS, and Cognizant.

Though for a comprehensive preparation, I also suggest you take a look at Java Programming Interview Exposed, which contains questions from all important Java topics, like Core Java, data structure and algorithms, multithreading, garbage collection, JVM internals, and frameworks like Spring and Hibernate.

Problem 1: Design a Vending Machine in Java (solution)

You need to design a Vending Machine which follows the following requirements:
1. It should accepts coins of 1,5,10,25, 50 Cents, i.e., penny, nickel, dime, and quarter as well as 1 and 2 dollar note

2. Allow user to select products like CANDY(10), SNACK(50), NUTS(90), Coke(25), Pepsi(35), Soda(45)

3. Allow users to take a refund by canceling the request.

4. Return the selected product and remaining change if any

5. Allow reset operation for vending machine supplier

You can try solving the problem on your own before looking at the solution. At least come up with classes and method names and relationship between classes. Preparing a UML diagram is bonus.

Problem 2: Design a URL shortener service like bit.ly? (solution)

You need to design a URL shortener service like bit.ly or goo.gl. You can insert the full URL and get a short one.

Your short URL should also record the stats about how many times it was accessed. Your system should also be able to handle concurrent users and millions of URL shortening per day. Think about auditing and bookkeeping, as well.

Btw, If you struggle to start with these questions, then you can also see the Grokking The System Design Interview, which contains a whole chapter on designing URL shortening services like TinyURL, Google URL, and Bitly.

Here is the system diagram from the same course, which explains the different components of a URL shortening service. I strongly suggest you check the course, this lesson is also available for a FREE preview.

Problem 3: Design an Efficient Parking Lot (Solution)

Designing a parking lot involves creating a system with user authentication for attendants, a centralized database for vehicle records, and an intuitive user interface for managing parking spaces.

The system would include features like entry/exit logging, real-time space availability updates, and online payment options. Security measures, such as surveillance cameras and access controls, would be implemented.

Your solution should provide both high level and low level design, including API design and Database or table design. It should also consider non-functional requirements like scalability (1000 places), avaibility, and Consistency. Once a reservation is made, the parking spot must be available for the user. No double-booking.

A mobile app or website could facilitate user reservations and provide navigation within the parking lot. Regular monitoring and maintenance would ensure optimal functionality, and a backup system would be in place for data recovery in case of system failures.

And, if you get stuck see Codemia.io’s editorial solution for designing an efficient Parking Lot . It’s one of the most completion solution of this problem including API design, database design, storage and bandwidth requirement, and much more.

Problem 4: Design a Lift or Elevator system in your programming language?

An elevator is a combination of at least two elevators, one going up and another coming down. The goal is to minimize the waiting time of the user. Make sure you how your design will evolve if a lift is installed on high-rise buildings over 20 floors.

How many lifts do you need to serve 40 floors with a waiting time of no less than 30 seconds on average. Think about the parking strategy of your lift, i.e., which floor they should be resting on or should they keep going up or down, etc.

If you need solution, you can watch the following video which explains how to design a lift system step by step but as I said, you must try to come up with basic design first.

And, if you need another solution of this system design problem then you can also see Codemia.io’ Object oriented problems. It’s one of the most completion solution of this problem including API design, database design, storage and bandwidth requirement, and much more.

Problem 5: Design and implement LRU cache in Java or C++?

An LRU cache stands for Least Recently Used. It should remove the least recently used item from the cache to make space for a new item. Think about the persistence strategy of the cache. how do you build cache after crash etc?

Let me give you a hint, you can use a LinkedHashMap to build an LRU cache in Java.

If you need full solution, you can also checkout this YouTube video by Backtobackswe, one of the best place to prepare for coding interviews

Problem 6: Design a Traffic Controller System for a Junction?

You need to design software to control traffic lights at a junction where traffic is coming from four sides. It should follow basic traffic rules, allow a pedestrian to cross the road, and traffic to pass in a reasonable time.

How do you optimize the waiting time with respect to high traffic from one direction, like during morning and evening rush hours?

If you need some help then a similar question about designing Airline Management System can be found on Grokking the Object-Oriented Design Interview course, you can go through that lesson to learn more about how to deal with such a question.

Problem 7: How do you Design Parking Garage?

This is another popular object oriented design and system design question which is often asked on FAANG companies. Many people said that this was asked to them during Amazon interview.

Most of the time interviewer will just give you vague requirement like this and you need to ask questions to clarify like how it should behave like how many parking slots, how a slot is taken, reserved or released etc.

If you need help to solve this problem, you can always checkout this video from Exponent’s YouTube channel.

If you don’t know Exponent is specialized in FAANG interview prep and they have an excellent System design course which has helped many people to clear System design interviews on FAANG companies.

Problem 8: Design a Trade Position Aggregator or Portfolio Manager?

You need to design a system where trades are fed at real time and you need to calculate live position by aggregating buy and sale trades for each symbol. You also need to allocate trades on accounts which is part of trade.

Here are rules and constraints you need to follow while designing this system:

1. When Direction is Buy and operation is NEW or AMEND, you need to increase the position as your exposure increases.

2. When Direction is Sell and operation is CANCEL, you need to increase the position as your exposure is not reducing.

3. When Direction is Buy and operation is Cancel reduce position;

4. When Direction is Sell, and operation is NEW or AMEND, reduce positions.

If you need a solution, you can see this tutorial where I have solved this question in Java, step by step.

Problem 9: How do you design a Distributed Message Queue?

This is another interesting Object oriented design question which is commonly asked during System design interviews. In this problem you need to design a distributed message queue.

Here are high level requirement:

1. Producers send messages
2. Consumers consume messages
3. Messages can be consumed repeatedly or only once

How will you approach this problem? To give you an hint, here is a nice diagram from ByteByteGo and Alex Xu, author of one of the most popular System design interview book called System Design Interview — An insider’s guide

Problem 10: How do you Design a Library Management System in Java or your favorite programming language?

This is another interesting problem to test your object oriented design skill, in this problem you need to design a library management system which should allow you to

1. Add new book,
2. Rent or issue a book to readers,
3. Send reminders when due date is near
4. and also print a report of overdue books.
5. It should also provide search functionality so that readers can find books easily.

This is a massive OOP Design problem and not easy to solve but not difficult as well. But if you need guidance, you can checkout the solution which is part of Educative’s Grokking the Object-Oriented Design Interview course but its freely available.

Problem 11 — How do you design a Blackjack game?

If you have played card games then you will be familiar with popular Card game now you need to use your object oriented programming skill to design and create a Blackjack game in Java or your favorite programming language.

The Grokking the Object-Oriented Design Interview course on Designgurus.io has a solution of that but its not free but don’t worry, here is a nice YouTube tutorial which will teach you how to create Blackjack in Java.

Other Popular Object Oriented Design Questions you can practice:

1. How to design a File sharing System?
2. How to design a Food delivery System like Foodpanda?
3. How to design an ATM machine?
4. How to design a Calendar Service?
5. How to design a Tic-Tac-Toe in Java?
6. How to design a Payment Gateway System?
7. How to design Tetris Game in Java?
8. How to design a car rental system
9. How to design a Movie Ticket system
10. Design a Chess game in Java
11. Design a Hotel Management System in Java?
12. How to design YouTube?
13. How to design a Chat system like WhatsApp or Facebook Messenger
14. WhatsApp System Design

That’s all in this list of frequently asked Object Oriented design questions from programming job interviews. As I said, object-oriented analysis and design are some of the most sought-after skills in job interviews.

If you can demonstrate excellent design and coding skills, along with writing a good JUnit test, it would create an excellent impression on the interviewer.

Everybody like good professional developers and unit testing is one of that thing which separate a professional to non-professional software engineers.

If you have been asked any other object-oriented design question or anything related to software design, feel free to share it with us.

Best System Design and Object Oriented Interview Resources

If you need more resources like books, and online courses to prepare for the System design Interview here are my recommendations:

• Mastering the System Design Interview by Frank Kane
• Object Oriented Design Problems at Codemia.io
• Grokking the System Design Interview on Educative
• Software Design and Architecture Specialization [Coursera]
• CodeKarle’s System Design Interview Course on Udemy
• System Design Interview course and Mock Interview by Exponent
• System Design Interview Course on ByteByteGo by Alex Wu
• Web Application & Software Architecture 101 [Educative.io]
• Pragmatic System Design [Udemy Course]
• Grokking Modern System Design for Software Engineers & Managers

Thanks for reading this article so far. If you like these Object-Oriented Design Questions, then please share it with your friends and colleagues. If you have any questions or doubt then, please drop a note,

P. S. — If you need more questions, I suggest you check out the Grokking the Object-Oriented Design Interview course on Educative, an interactive learning platform. This course is a complete guide to master the OODI. It is designed by the hiring managers of Google, Facebook, Microsoft, and Amazon and contains solutions to some of the frequently asked object-oriented design questions from these tech giants.

Grokking the Object Oriented Design Interview - Learn Interactively

Object-oriented design has always been a critical part of the software engineering interview process. Most of the…

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