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How to Comment and Document Code in JavaScript?

Commenting is essential in JavaScript for better readability, debugging, and documentation. JavaScript supports single-line, multi-line, and JSDoc comments.

1️⃣ Single-Line Comments​

Use // for short explanations or to disable code on a single line. Ctrl + /

// This is a single-line comment
let x = 10; // Variable storing a number

✅ Best for: Quick notes and debugging.

2️⃣ Multi-Line Comments​

Use /* ... */ for multi-line explanations. Shift + Alt + A

/*
This function calculates the sum of two numbers
and returns the result.
*/
function add(a, b) {
  return a + b;
}

✅ Best for: Describing functions, logic, or sections of code.

3️⃣ Inline Documentation / JSDoc Comments​

JSDoc is used for documenting functions, parameters, and return types. Shift + Alt + A

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

✅ Best for: Professional documentation, IDE tooltips, and API references.

tip

💡 Best Practices for Commenting​

✔ Write meaningful comments, not obvious ones.
✔ Use JSDoc for functions, classes, and APIs.
✔ Avoid over-commenting; code should be self-explanatory.