JavaScript comments

JavaScript comments are an essential part of any programming language. They are used to add notes, explanations, and documentation to the code. Comments are ignored by the JavaScript engine and do not affect the execution of the code. They are an excellent way to make the code more readable and understandable for other developers or for yourself when you come back to the code later.

There are two types of comments in JavaScript.

  1. Single-line Comment
  2. Multi-line Comment

In this tutorial, we will cover the basics of JavaScript comments, including:

  • Single Line Comments: Single line comments start with two forward slashes (//) and continue to the end of the line. They are used to add brief notes or explanations to the code. For example:
1// This is a single line comment

comment at the end of another statement

1var a=5; # assign 5 to variable a
  • Multi-Line Comments: Multi-line comments start with a forward slash and an asterisk /* and end with an asterisk and a forward slash */. They can span multiple lines and are used to add detailed explanations or documentation to the code. For example:
1/* This is a
2multi-line comment
3that can span
4multiple lines */

this can be used to block a single line

1/* comment line*/
  • Todo Comments: Todo comments are used to leave a reminder or to-do note in the code. They start with the word "TODO" and can be single or multi-line comments. For example:
1// TODO: Add error handling for this function
  • Block Comments: Block comments are similar to multi-line comments but they are specifically used to comment out a block of code, so it is not executed. They start with /* and end with */. For example:
1/*
2  var x = 0;
3  var y = 0;
4*/
  • JSDoc Comments: JSDoc comments are a specific type of comment format used to generate documentation for JavaScript code. They start with /** and end with */. They can be used to provide information about the function, its parameters, and return values. They are often used to generate API documentation. For example:
1/**
2 * @function add
3 * @param {number} x - the first number
4 * @param {number} y - the second number
5 * @return {number} the sum of x and y
6 */
7function add(x, y) {
8  return x + y;
9}

It's good practice to add comments in your code, especially if you are working on a team. It helps other developers to understand what the code is doing and makes it easier to maintain the code. Comments should be clear, concise, and accurate. And also it's good practice to update your comments if you make any changes to the code.

comments are an essential part of any JavaScript development, and they should be used liberally throughout the code. They can help to make the code more readable, understandable, and maintainable. With the help of comments, you can make your code more organized and easy to work with.