comments

Comments in JavaScript are used to explain code and make it more readable. They can also be used to prevent execution when testing alternative code. There are two types of comments in JavaScript:

Single-line comments: These comments start with //. Any text between // and the end of the line is ignored by JavaScript (will not be executed).

// This is a single-line comment
let x = 5; // This is another single-line comment

Multi-line comments: These comments start with /* and end with */. Any text between /* and */ will be ignored by JavaScript.

/*
 This is a multi-line comment
 It can span multiple lines
*/
let y = 10;

Best Practices for Using Comments

• Clarity: Use comments to explain the "why" behind your code, not the "what". The code itself should be self-explanatory when it comes to the "what".
• Conciseness: Keep comments concise and to the point.
• Update: Ensure comments are updated when the code changes to avoid discrepancies between code and comments.
• Avoid Redundancy: Do not state the obvious in comments. For instance, avoid comments like // increment x by 1 for code like x++;.

Here's an example demonstrating these practices:

// Calculate the factorial of a number
function factorial(n) {
   // If the number is less than 0, reject it
   if (n < 0) return -1;
   // If the number is 0, its factorial is 1
   if (n === 0) return 1;
   // Otherwise, recursively calculate the factorial
   return n * factorial(n - 1);
}
/*
 Example usage:
 factorial(5); // returns 120
*/

Using comments effectively can greatly enhance the maintainability and readability of your code.