JavaScript is among the most commonly utilized programming languages for web development. Regardless of your expertise in programming, crafting code that is both clear and understandable is essential. One of the most effective methods to achieve this clarity is by incorporating comments within your code.
This article will thoroughly explore the topic of JavaScript comments, encompassing their various types, functions, and recommended practices. By the conclusion, you will possess a solid comprehension of how to effectively utilize comments within your code.
Definition
JavaScript comments serve as a valuable method for conveying information. They are utilized to provide insights about the code, issue warnings, or offer recommendations, allowing the end user to interpret the code with greater ease.
What Are JavaScript Comments?
Text lines that the JavaScript engine disregards while executing code are referred to as comments. They serve as annotations or explanations for developers who may read or modify the code in the future.
Effective use of comments is helpful:
- Make the code easier to read.
- Describe complex logic.
- Parts of the code can be temporarily disabled for debugging.
- Provide future developers with helpful documentation.
Types of JavaScript Comments
JavaScript supports two distinct forms of comments.
- Single-line Comment
- Multi-line Comment
JavaScript Single line Comment
It is denoted by two forward slashes (//). This notation can be utilized both preceding and succeeding the statement.
Single-line comments are useful for brief notes or clarifications. In JavaScript, these comments begin with two forward slashes (//). The JavaScript interpreter disregards everything that follows // on that line.
Syntax
The syntax demonstrates the representation of a single-line comment.
// This is a single-line comment
Example 1
//A single line comment
console.log("Example");
Output:
Example
Example 2
let a = 10;// declare a, give it the value of 10
let b = a + 21; // declare b, give it the value of a + 21
console.log(b);// printing b
Output:
JavaScript Multi-line Comment
This feature allows for the inclusion of both single-line and multi-line comments, making it more user-friendly.
A forward slash followed by an asterisk denotes it, followed by an asterisk and a forward slash.
You have the ability to compose more extensive descriptions utilizing multi-line comments. These comments are initiated with / and concluded with /. Everything enclosed within these markers is regarded as a comment.
Syntax
The multi-line comment is represented in the syntax. It can be utilized before, after, and in the midst of the code statement.
/* your code here */
Example
Consider the illustration of a multi-line comment, which is positioned prior to the statement.
Example
/* It is a multi-line comment.
It will not be displayed */
console.log("Welcome to our tutorial");
Output:
The result displays the Multi-line comment utilized in JavaScript.
Output:
Welcome to our tutorial
The Best Ways to Write Comments
Comments are useful, but when used improperly, they can confuse. Adhere to these recommended practices:
- Clear comments: Compose comments that are clear and short to remove unnecessary explanations.
- Use comments to explain why, not what: The code itself should be self-explanatory;
- Maintain comments up to date: If the code changes and, make the necessary updates.
- Steer clear of too many comments: They can make the code more difficult to read.
- Use meaningful names for variables and functions: Give variables and functions meaningful names to cut down on the amount of comments required.
When Should I Use Comments?
The use of comments should be prudent. In the following situations, comments can be useful:
- Clarifying complex logic: A comment can assist others in understanding the intent of a complex piece of code.
- Function and variable descriptions: Give a brief explanation of the purpose of each function or variable.
- Debugging and testing: Programming can be temporarily disabled without being deleted during debugging and testing.
- Marking TODOs and Fixes: Making notes for upcoming enhancements is known as "marking TODOs and fixes."
JavaScript Comments to Prevent Execution
In JavaScript, we have the option to employ // for single-line comments or /…/ for multi-line comments to influence the execution of the code. By utilizing comments in JavaScript, we can halt the execution of specific code segments, making them ideal for testing purposes.
Example 1
function sum(){
let a = 12;
let b = 2;
let c = a + b;
//console.log(a + b);
console.log(c);
}
sum();
Output:
Example 2
function sub(){
let a = 12;
let b = 2;
/*let c = a + b;
console.log(a + b);*/
let c = a - b;
console.log(c);
}
sub();
Output:
Conclusion
To summarize, producing understandable and maintainable JavaScript code necessitates the incorporation of comments. These annotations aid in troubleshooting, provide documentation, and clarify complex logic. However, it is essential to use them judiciously, as an excessive number of redundant comments can clutter the code.