How to Make Multi-line Comment in JavaScript?

At first, coding can seem difficult especially for beginners. This article aims to assist you in simplifying matters. This article will guide the process of “commenting out multiple lines in JavaScript”. Mastering the skill of commenting on your code is crucial for every programmer. This method allows for the temporary deactivation of specific code segments without the need for their removal. This is a good practice for debugging, testing or just leaving yourself or other developer notes.

Before we begin, let's define what is meant by "commenting out" code. A comment in programming refers to a line of text that is not executed by the computer. It's provided solely for the benefit of human readers to give notes or explain in more detail what a bit of code does. Commenting out code involves transforming specific lines of code into comments which the computer does not execute.

This article will cover the subsequent topics.:

• Single-line comments in JavaScript
• Using single-line comments to comment out multiple lines
• Multi-line comments in JavaScript
• Using multi-line comments to comment out multiple lines
• Proper use of each commenting technique

Single-line comments in JavaScript

JavaScript has two ways of making comments: single-line comments and multi-line comments. To begin, we will discuss single-line comments.

A single-line comment is initiated by placing two forward slashes //. Everything typed in on the same line beyond this will be a comment to the program and will never be executed. For example:

Code

Output

In this instance, the initial line serves as a single-line comment while the subsequent line contains a comment positioned after the console.log() statement. The computer will disregard both comments during code execution.

Using single-line comments to comment out multiple lines

To comment out several lines using single-line comments, you can easily prepend two forward slashes // to the start of each line intended for commenting. For instance:

Code

Output

In this instance, all three lines serve as comments which means that no code will be executed at any time.

Although this method does become a bit tedious to manage many lines to comment out but it is a valid method of commenting out multiple lines of code.

Multi-line comments in JavaScript

Now let's consider multi-line comments. In JavaScript, multi-line comments are initiated with a combination of forward slashes and asterisks. The sequence /* indicates the start of a comment while */ signifies its conclusion. Anything within these symbols will be interpreted as a comment and thus not processed by the computer. Here is an example code:

Code

Output

In this instance, the initial three lines are designated as a multi-line comment which allows the console.log() statement to execute.

Multi-line comments can extend across numerous lines which provides a more effective method for commenting out several lines of code compared to single-line comments.

Using multi-line comments to comment out multiple lines

To disable multiple lines of code, it is necessary to enclose the selected code within /* and */. For example:

Code

Output

In this instance, both console.log() statements are contained within a multi-line comment which prevents their execution.

Proper use of each commenting technique

Having grasped the concepts of single-line and multi-line comments, you may be contemplating the most effective method for commenting out several lines of code. Below are some general recommendations to assist you in making your decision:

1. Single-line comments are highly effective and straightforward for commenting out one or two lines.
2. It is much more convenient and readable to use multi-line comments, when a more extensive block of code is needed to be commented out.
3. In the case of team collaboration or code sharing, it is better to use multi-line comments for long parts of the code because they give a clearer visual separation and are easier to understand for others.

Conclusion

In summary, being able to comment out more lines in JavaScript is a highly important proficiency for any programmer. For example, single-line comments might be useful for short annotations or to make one or two lines of the code not execute while multi-line comments are needed for entire sections of code or when clear explanations are required. With a better understanding of when and how to use each commenting style, you will be in a much better position to create clean, efficient and thoroughly documented code.