The Essential Guide to Code Commenting: Best Practices, Types, and Documentation.

#webdev #ai #javascript #tutorial

When writing code, communication isn’t just between you and the machine, but it’s also between you and other developers (or your future self!). Clear and effective code commenting plays a vital role in making your code understandable, maintainable, and scalable.

In this guide, we’ll explore:

What code comments are and why they matter
Different types of comments: inline vs. block
The power of JSDoc for inline documentation
How to balance commenting to avoid clutter
Advantages of structured documentation over simple comments

What Are Code Comments?

Code comments are notes written inside your source code to explain what the code does, why certain decisions were made, or how to use a function or module. They don’t affect the program execution but are critical for clarity.

Comments help:

Other developers quickly understand your code
You recall your own logic months later
Tools and IDEs provide better assistance (when using structured comments like JSDoc)

Types of Comments: Inline vs. Block

Inline Comments

Written on a single line, usually beside the code they explain
Start with // in JavaScript
Ideal for brief explanations or notes

Example:

let count = 10;  // number of items to process

Block Comments

Can span multiple lines, enclosed between /* and */
Used for longer explanations, function headers, or multi-line notes

Example:

/*
  Calculates the sum of two numbers.
  This function takes two numeric inputs and returns their sum.
*/
function add(a, b) {
  return a + b;
}

Why Use JSDoc? The Power of Structured Inline Documentation

While simple comments are helpful, JSDoc takes documentation to the next level by providing a structured way to describe functions, parameters, return values, and more — all inline with your code.

Example JSDoc usage:

/**
 * Adds two numbers.
 * @param {number} a - First number
 * @param {number} b - Second number
 * @returns {number} Sum of a and b
 */
function add(a, b) {
  return a + b;
}

Benefits of JSDoc over simple comments:

Provides type information for parameters and return values
Helps IDEs (like VSCode) show helpful hints and autocomplete suggestions
Enables automatic generation of API documentation with tools like jsdoc CLI
Improves readability by enforcing a standard format
Clarifies the intent and usage of functions better than generic comments

Balancing Comments: When and How Much to Comment?

While commenting is crucial, too many comments can clutter code and reduce readability. Here are some tips for a good balance:

Write self-explanatory code first: Use meaningful variable and function names so that the code itself communicates its purpose. This reduces the need for excessive commenting.
Comment the “why,” not the “what”: Explain the reason behind complex logic, not obvious code. For example, avoid comments like // adds two numbers on a simple addition function.
Document public APIs and complex functions: Use JSDoc or block comments to describe how to use functions, especially if they have multiple parameters or tricky behavior.
Avoid redundant comments: Comments that just repeat what the code does add no value and should be removed.

Inline Comment vs. JSDoc: A Quick Comparison

Aspect	Inline Comment (`//`)	JSDoc (`/** ... */`)
Purpose	Brief notes or reminders	Structured documentation of code
Format	Simple, unstructured	Formal tags like `@param`, `@returns`
IDE Support	Basic syntax highlighting	Enhanced support: hints, autocomplete
Documentation Generation	None	Supports automatic API docs

Example: Comparing Inline Comment and JSDoc

Inline Comment

// Adds two numbers and returns the result
function add(a, b) {
  return a + b;
}

JSDoc Comment

/**
 * Adds two numbers.
 * @param {number} a - First number
 * @param {number} b - Second number
 * @returns {number} Sum of a and b
 */
function add(a, b) {
  return a + b;
}

The JSDoc comment provides richer information and better tool support.

Summary:

Good commenting is an art. Writing clear, concise, and meaningful comments, especially using tools like JSDoc — makes your code more understandable and maintainable for everyone, including your future self.

Always strive to: