In this comprehensive course on object-oriented programming (OOP) in modern JavaScript, you'll explore fundamental concepts and advanced techniques to enhance your mastery of JavaScript's OOP capabilities.

We begin by examining the basics, including object literals, square bracket usage, and property shorthand, alongside restrictions on property names and object iteration using `for...in` loops.

Advancing further, we delve into complex topics like object references, duplication, and reference-based comparison. You'll learn to modify constant objects, clone objects with nested structures, and grasp methods within objects, with a focus on the `this` keyword's significance.

Next, we introduce constructor functions and the `new` operator, clarifying constructor return values and demonstrating how to utilize optional chaining for error prevention and code optimization.

You'll also develop a profound understanding of symbol types, their global applications, and system symbol utilization. Additionally, we'll address object-to-primitive conversion strategies, including hints, and examine `toString` and `valueOf` methods for effective conversion management.

By course end, you'll possess a comprehensive grasp of modern JavaScript's OOP concepts, enabling you to write concise, efficient code and confidently tackle intricate programming challenges. This knowledge will not only elevate your JavaScript skills but also enhance your ability to design robust and scalable applications, making you a more versatile and valuable developer in today's competitive landscape.