In JavaScript, comments are used to improve code readability and provide explanations. There are two primary types of comments: single-line comments and multi-line comments.
Single-Line Comments
Single-line comments begin with `//`. Everything after `//` on the same line is ignored by the JavaScript engine.
// This is a single-line comment
let a = 5; // This is an inline comment
Multi-Line Comments
Multi-line comments start with `/*` and end with `*/`. They can span across multiple lines.
/*
This is a multi-line comment.
It can span multiple lines.
*/
let b = 10;
Best Practices for Comments
1. Describe Code Functionality:
Use comments to explain what specific sections of code do, especially if the logic is complex.
2. Provide Context:
Explain why a particular solution was chosen or provide context for complex algorithms.
3. Mark TODOs:
Use comments to note areas that need further development or refinement.
Examples
Single-Line Comment Example
let sum = a + b; // Add a and b to get the sum
Multi-Line Comment Example
/*
This function calculates the sum of two numbers.
It takes two parameters and returns their sum.
*/
function add(x, y) {
return x + y;
}
Using Comments to Temporarily Disable Code
let value = 10;
// value = 20; // This line is temporarily disabled
console.log(value); // Outputs: 10
Comments are crucial for making your code understandable and maintainable for yourself and others who might work with your code in the future.