search
HomeWeb Front-endFront-end Q&AIn-depth discussion of the application and usage of set method in JavaScript

When programming in JavaScript, sometimes we need to modify the properties of objects. For safety and standardization, we usually use the set method to set object properties. This article will delve into the application and usage of the set method in JavaScript.

1. What is the set method?

The set method is an accessor in JavaScript that can be used to set the property value of an object. The set method is automatically called when the attribute value is assigned. This method can provide additional control and inspection of the attribute. In addition, the set method is generally used together with the get method to form a complete property accessor.

2. The syntax of the set method

The syntax of the set method is as follows:

set propName(value) {
    // 操作
}

Among them, propName is the attribute name to be set, and value is the attribute value to be set. The operations inside the set method can be any legal JavaScript code.

3. Usage of set method

  1. Control attributes

Through the set method, we can control and check the value of the attribute. For example, we can limit the age attribute of an object to no more than 100:

let person = {
    _age: 0,
    set age(value) {
        if (value > 100) {
            console.log("年龄不能大于100!");
            return;
        }
        this._age = value;
    },
    get age() {
        return this._age;
    }
};
person.age = 120; // 输出 "年龄不能大于100!"
person.age = 30; // 设置成功

In the above code, when the age is set to be greater than 100, the set method will return and output "The age cannot be greater than 100!" Prompt information, thus playing the role of attribute value control.

  1. Modify attributes

In addition to controlling attribute values, we can also perform some special processing on attributes inside the set method. For example, we can convert a string attribute to uppercase and lowercase:

let person = {
    _name: "",
    set name(value) {
        if (typeof value !== "string") {
            console.log("姓名必须是一个字符串!");
            return;
        }
        this._name = value.toLowerCase();
    },
    get name() {
        return this._name;
    }
};
person.name = "JACK"; // 设置成功,_name属性值为"jack"

In the above code, the set method internally converts the incoming value to lowercase, thus realizing the modification and processing of the attribute. .

  1. Set read-only attributes

If we want a certain attribute to be read only and not allowed to be modified, we can use the set method to achieve this. For example:

let person = {
    _age: 18,
    set age(value) {
        console.log("年龄不能被修改!");
    },
    get age() {
        return this._age;
    }
};
person.age = 20; // 输出 "年龄不能被修改!"
console.log(person.age); // 输出 18

In the above code, when the age attribute of the person object is called for assignment, the set method will output the prompt message "Age cannot be modified!", thereby setting the read-only attribute. .

4. Notes on the set method

  1. The properties of an object can be set with both get and set methods at the same time, or only one of them can be set.
  2. The set method is generally used together with the get method to form a complete attribute accessor.
  3. If only the set method is set and the get method is not set, undefined will be returned when reading the property.
  4. Some additional operations and controls can be performed inside the set method, such as checking and modifying attribute values.
  5. The set method can be used to implement read-only attributes, as well as access control and processing of attributes.

5. Conclusion

Through the above introduction, we understand the usage and application of the set method in JavaScript. The set method can be used to control the setting of attribute values, modify attributes, set read-only attributes, etc. In actual programming, reasonable use of the set method can improve the readability, robustness and security of the code. Therefore, mastering the application and usage of the set method is very helpful for improving JavaScript programming skills.

The above is the detailed content of In-depth discussion of the application and usage of set method in JavaScript. For more information, please follow other related articles on the PHP Chinese website!

Statement
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
What is useEffect? How do you use it to perform side effects?What is useEffect? How do you use it to perform side effects?Mar 19, 2025 pm 03:58 PM

The article discusses useEffect in React, a hook for managing side effects like data fetching and DOM manipulation in functional components. It explains usage, common side effects, and cleanup to prevent issues like memory leaks.

Explain the concept of lazy loading.Explain the concept of lazy loading.Mar 13, 2025 pm 07:47 PM

Lazy loading delays loading of content until needed, improving web performance and user experience by reducing initial load times and server load.

What are higher-order functions in JavaScript, and how can they be used to write more concise and reusable code?What are higher-order functions in JavaScript, and how can they be used to write more concise and reusable code?Mar 18, 2025 pm 01:44 PM

Higher-order functions in JavaScript enhance code conciseness, reusability, modularity, and performance through abstraction, common patterns, and optimization techniques.

How does currying work in JavaScript, and what are its benefits?How does currying work in JavaScript, and what are its benefits?Mar 18, 2025 pm 01:45 PM

The article discusses currying in JavaScript, a technique transforming multi-argument functions into single-argument function sequences. It explores currying's implementation, benefits like partial application, and practical uses, enhancing code read

How does the React reconciliation algorithm work?How does the React reconciliation algorithm work?Mar 18, 2025 pm 01:58 PM

The article explains React's reconciliation algorithm, which efficiently updates the DOM by comparing Virtual DOM trees. It discusses performance benefits, optimization techniques, and impacts on user experience.Character count: 159

What is useContext? How do you use it to share state between components?What is useContext? How do you use it to share state between components?Mar 19, 2025 pm 03:59 PM

The article explains useContext in React, which simplifies state management by avoiding prop drilling. It discusses benefits like centralized state and performance improvements through reduced re-renders.

How do you prevent default behavior in event handlers?How do you prevent default behavior in event handlers?Mar 19, 2025 pm 04:10 PM

Article discusses preventing default behavior in event handlers using preventDefault() method, its benefits like enhanced user experience, and potential issues like accessibility concerns.

What are the advantages and disadvantages of controlled and uncontrolled components?What are the advantages and disadvantages of controlled and uncontrolled components?Mar 19, 2025 pm 04:16 PM

The article discusses the advantages and disadvantages of controlled and uncontrolled components in React, focusing on aspects like predictability, performance, and use cases. It advises on factors to consider when choosing between them.

See all articles

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

AI Hentai Generator

AI Hentai Generator

Generate AI Hentai for free.

Hot Article

R.E.P.O. Energy Crystals Explained and What They Do (Yellow Crystal)
2 weeks agoBy尊渡假赌尊渡假赌尊渡假赌
Repo: How To Revive Teammates
4 weeks agoBy尊渡假赌尊渡假赌尊渡假赌
Hello Kitty Island Adventure: How To Get Giant Seeds
4 weeks agoBy尊渡假赌尊渡假赌尊渡假赌

Hot Tools

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

SecLists

SecLists

SecLists is the ultimate security tester's companion. It is a collection of various types of lists that are frequently used during security assessments, all in one place. SecLists helps make security testing more efficient and productive by conveniently providing all the lists a security tester might need. List types include usernames, passwords, URLs, fuzzing payloads, sensitive data patterns, web shells, and more. The tester can simply pull this repository onto a new test machine and he will have access to every type of list he needs.

MantisBT

MantisBT

Mantis is an easy-to-deploy web-based defect tracking tool designed to aid in product defect tracking. It requires PHP, MySQL and a web server. Check out our demo and hosting services.

mPDF

mPDF

mPDF is a PHP library that can generate PDF files from UTF-8 encoded HTML. The original author, Ian Back, wrote mPDF to output PDF files "on the fly" from his website and handle different languages. It is slower than original scripts like HTML2FPDF and produces larger files when using Unicode fonts, but supports CSS styles etc. and has a lot of enhancements. Supports almost all languages, including RTL (Arabic and Hebrew) and CJK (Chinese, Japanese and Korean). Supports nested block-level elements (such as P, DIV),

ZendStudio 13.5.1 Mac

ZendStudio 13.5.1 Mac

Powerful PHP integrated development environment