comment in javascript

Understanding how to comment in JavaScript is crucial for both writing and understanding code. Effective use of comments can drastically improve code readability and maintainability.

Single Line Comment

Code snippet

In JavaScript, anything following // on a line of code is a single line comment. Here’s an example:

// This is a single line comment in JavaScript
alert("Hello World!"); // This console log statement is not commented out

Code Explanation

The first line of the code snippet is a comment, thus it’s not run during the execution. The third line contains Javascript alert command as well as a comment. The rule here is JavaScript will execute everything before // and will ignore the rest.

This is particularly useful when you want to leave a note about a specific line of code, or temporarily disable a piece of JavaScript without deleting it.

Multi-Line Comment

Code snippet

For multi-line comments, you can use /* (slash and an asterisk) to start the comment, and */ (asterisk and a slash) to end the comment. Here is an example:

/* This is a multi-line comment 
and it spans more than one line.*/
alert("Hello World!");

Code Explanation

The entire block of text in the first two lines is commented out, thus it is not run during execution. Just like single-line comments, it’s a good way to remember why certain decisions were made or disable a block of code.

In conclusion, the ability to effectively comment on your code is a key skill for any developer. It helps to make your code more comprehensible to others, and it can also serve as reminders to you when you revisit your code in the future.