Comments in JavaScript

Comments are a vital tool in programming, allowing developers to add explanatory notes, disable parts of the code temporarily, or document their thought process. In JavaScript, comments help make code easier to understand, debug, and maintain. Whether you're documenting functionality or marking areas for improvement, effective commenting is a skill every programmer should master.

In this section, we’ll cover the following topics.

Comments in Programming

What Are Comments in Programming?

Comments are annotations that improve code readability and maintainability. They serve as a guide for developers revisiting their work and help teams collaborate effectively. For example, comments can explain the purpose of a specific function, highlight areas that need refactoring, or even outline the steps of a complex algorithm.

Differences in Comments Across Programming Languages

The syntax for comments varies across programming languages. Here's a quick comparison:

HTML:

• Single-line and Multi-line comments: Use <!-- Comment -->.

CSS:

• Single-line and Multi-line comments: Use /* Comment */.

PHP:

• Single-line comments: Use // Comment or # Comment.
• Multi-line comments: Use /* Multi-line comments */.

Python:

• Single-line comments: Use # Comment.
• Multi-line comments: Use triple quotes """ Multi-line comments """

Understanding these differences ensures you use comments effectively in any environment.

Types of JavaScript Comments

JavaScript offers two types of comments: single-line and multi-line.

Single-Line Comments (//)

Single-line comments, denoted by //, are used for brief notes or to disable a single line of code.

Example:

// This is a single-line comment.
let x = 10; // Assign 10 to x.

Multi-Line Comments (/* */)

Multi-line comments, enclosed by /* and */, are used for longer explanations or to comment out blocks of code.

Example:

/*  
This is a multi-line comment.  
It spans multiple lines.  
*/
let y = 20;

The multi-line commenting approach is consistent across JavaScript, CSS, and PHP. It allows you to disable or explain several lines of code in one go, making it a versatile option.

Commenting Features in Visual Studio Code

Visual Studio Code (VSC) is one of the most popular text editors for developers, offering powerful features for writing, managing, and enhancing comments. Its intuitive design, extensive plugin ecosystem, and performance make it a preferred choice for coding.

Comment Shortcuts

VSC simplifies the process of adding comments with keyboard shortcuts:

Use Ctrl + / (Windows/Linux) or Cmd + / (Mac).

• For single-line comments, this shortcut adds or removes // at the start of the selected line(s).
• For multi-line comments, select a block of text, and the same shortcut toggles between commented and uncommented states.

These shortcuts save time and make commenting more efficient.