How to make multi-line comments in JavaScript

JavaScript is a widely used computer programming language that is widely used in website development, application development, game development and other fields. Comments are an important part of writing JavaScript programs. They can help developers better understand the code and make the code easier to maintain. In JavaScript, comments can come in two forms: single-line comments and multi-line comments. This article will introduce the syntax and application of JavaScript multi-line comments.

1. JavaScript multi-line comment syntax

In JavaScript, the syntax of a multi-line comment is a piece of text starting with "/" and ending with "/". The specific expression is as follows:

/*
这是注释的内容
这是注释的内容
这是注释的内容
*/

In multi-line comments, you can add any number of lines of text. The text content will be ignored by the JavaScript interpreter and will not have any impact on the execution of the program.

2. Application of JavaScript multi-line comments

Multi-line comments have many application scenarios in JavaScript. Here are some common applications.

1. Comments on classes, functions, and methods

When writing classes, functions, and methods in JavaScript, developers usually add comments to them to make the code more clear. Easy to understand. The following is an example:

/**
 * 计算两个数字的和
 * @param {number} a - 第一个数字
 * @param {number} b - 第二个数字
 * @returns {number} - 两个数字的和
 */
function add(a, b) {
    return a + b
}

/*
这是一个例子说明如何添加函数的注释
*/

Through comments, developers can clearly understand the parameter types, return value types and functional functions of the function.

2. Debugger

When debugging a JavaScript program, multi-line comments can help developers debug the program. Adding comments in the program allows developers to temporarily turn off a section of code for debugging, as shown below:

/*
这段代码不起作用，暂时注释掉
function doSomething() {
    // code here
}
*/

When you need to re-enable the code, just uncomment it.

3. Cancel the execution of code

In some cases, developers may need to add temporary multi-line comments to the program to cancel the execution of the code. For example, when you need to disable a certain piece of code, you can use a multi-line comment to do so, as shown below:

/*
function doSomething() {
    // code here
}
*/

By commenting out this piece of code, you can quickly disable its execution.

4. Document generator

In document generators such as jsdoc, multi-line comments can be used to generate the comment content of the document. Document generators such as jsdoc can automatically generate API documentation by reading comments in JavaScript files, providing developers with better code usage instructions and documentation.

3. Summary

JavaScript multi-line comments are an essential part for developers when writing code. By adding comments, developers can better understand the function and role of the program, while also making the program easier to maintain and debug. This article introduces the syntax and application scenarios of JavaScript multi-line comments. I hope it can be helpful to readers in JavaScript coding.

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