JavaScript comments are used to provide explanations, clarifications, and notes within your code. Comments are ignored by the JavaScript engine and are meant for developers to better understand the code. There are two primary ways to add comments in JavaScript: single-line comments and multi-line comments.

Single-line comments: These are used to add comments on a single line. You can use them by starting a line with //.

// This is a single-line comment
let x = 10;  // You can also add comments at the end of a line of code

Multi-line comments: These are used to add comments that span multiple lines. Multi-line comments start with /* and end with */.

/*
   This is a multi-line comment.
   You can add comments on multiple lines.
*/
let y = 20;

Comments are useful for documenting your code, explaining your thought process, or leaving notes for yourself and other developers who may read or work on your code. Here are some examples of how comments can be used:

Example 1: Commenting Code for Clarity

// Calculate the area of a rectangle
let length = 10;  // Length of the rectangle
let width = 5;    // Width of the rectangle
let area = length * width;  // Calculate the area

In this example, comments are used to explain the purpose of each variable and the calculation.

Example 2: Adding Documentation

/*
   Function to greet a user.
   @param {string} name - The name of the user.
   @returns {string} A greeting message.
*/
function greetUser(name) {
    return "Hello, " + name + "!";
}

Multi-line comments are commonly used for documenting functions or providing information about the function's parameters and return values.

Example 3: Temporary Code Removal

// Disable the following code for testing
// let debug = true;
// ...

// Temporary code for testing
// if (debug) {
//     // Debugging code here
// }

You can comment out code temporarily to test or debug other parts of your program.

Remember that good code should be self-explanatory, but comments can provide additional context or clarify complex logic. Be mindful of over-commenting, as excessively commented code can be harder to read. Comments are most valuable when they explain "why" something is being done rather than "what" is being done, as the "what" is often evident from the code itself.

Which of the following operators is used as a comment in JavaScript?

1. //
2. <!-- →
3. #
4. **

Answer: 1