Gain insights into intermediate JavaScript, mastering interview questions, common design patterns, and deep understanding of the language. Learn with expert Arnav Aggarwal's engaging teaching method.

This is for those familiar with the basics of JavaScript and looking to advance their knowledge and really understand how the language works. We'll cover topics that are essential to help you read, understand, and write better code. Before starting, you should be familiar with the basics of variables, functions, and loops in JavaScript.

This course will enable you to master JavaScript interview questions that stump most developers. You'll be able to talk intelligently about the fundamentals of the language and about common design patterns.

This course has been created by Arnav Aggarwal, a full-stack engineer. Having attended a coding boot camp and having taught at another one, Arnav has extensive experience understanding how new developers learn to code. In under a month, Arnav's published articles on JavaScript concepts have received over 50,000 views and have been featured as staff selections on Medium.com and codementor.io because of their educational value.

Yangshun Tay

In response to "The Complete Rules to 'this'": 
Clear and to the point. This is one of the best explanations on “this” available on the net. I particularly liked how you explained about global function invocation being implicit method invocation on window. Thank you.

Front-End Engineer at Facebook

Jaya Arasalike

This is an excellent javascript course. Arnav covers deep basics well by giving enough examples and explaining what exactly is happening - how/ when values are changing. His diagrams, for example local vs global scope or the table representation for values vs reference makes reader easily understand what he is talking about and how it works. The quizzes at the end of each chapter, makes one think through what he or she has learnt and apply those concepts to arrive at the answers. That helps a lot in nailing down the core concepts. 

Bootcamp Graduate & Full-Stack Developer

Irshaad Bijan Adatia

In response to the Prototypes & Inheritance articles:

Having just finished a JavaScript course in college, this was a great stepping stone to move into an intermediate level if JS. Thank you.

It was also very well laid out.

Computer Science Student

Step Up Your JS: A Comprehensive Guide to Intermediate JavaScript

# Value vs. Reference with `const`

There's a small piece of the discussion of `const` that was left out in the related previous lesson. We haven't discussed how it works with objects. To truly understand that, we first needed an understanding of value vs. reference in JS. With that understanding, we can now finish our discussion of `const`.

## Objects are mutable

When using `const`, with primitives, once a value is assigned to a constant variable, that variable is immutable. It cannot be changed.

With reference types, namely arrays and objects, it is the reference that cannot be changed. Writing `const arr = [];` means that `arr` always has a reference to the array that was just created.

Unlike primitives, the array itself is mutable and can be manipulated. Values can be inserted, removed, sorted, etc. Anything can be done to it. We just can't reassign `arr` to a different reference or value.

We'll learn how 'const' works with the concept of value vs. reference in JS.

Behavior of Functions and Variables

Essential Modern JavaScript - ES2015+ In Depth

Object Oriented Programming: The Core

Object Oriented Programming: `this` and Inheritance

Introduction to Functional Programming

Functional Programming: Arrays and their Powerful Methods

Functional Programming: Objects and their Powerful Methods

A Dive into Asynchronous JavaScript

Advanced Modern JavaScript - Cutting Edge ES2015+

Conclusion

Value vs. Reference with ES2015

Value vs. Reference with `const`

Value vs. Reference with ES2015

Value vs. Reference with const

Value vs. Reference with `const`