Web Front-endJS TutorialHow to call a function with a section appended to parameters in JavaScript?
In JavaScript, you can call a function by passing parameters to it. However, sometimes it is necessary to call a function with some parameters already populated. This can be done using a technique called partial function application.
What is partial function application?
Partial function application is a way to create a new function by "pre-populating" some parameters of an existing function. This is useful when you want to create a new function that is similar to an existing function but has some parameters set.
For example, suppose you have a function that calculates the area of a rectangle. The function takes two parameters - the width and height of the rectangle.
Now imagine you want to create a new function to calculate the area of a square. This new function will be similar to the existing function, but it will only require one parameter - the sides of the square.
This is where partial function applications come in. You can use the partial function app to create a new function that is a "partial" version of an existing function. This new function will have the first parameter (width) already set, and only require the second parameter (height).
How to use partial function application in JavaScript?
There are a few different ways to use partial function applications in JavaScript.
method 1
The most common method is to use the bind() method.
The bind() method is a way to create a new function from an existing function. The bind() method takes two parameters: the function to be bound, and the value to be bound to the first argument of the function.
For example, suppose you have the following function -
function add(a, b) {
return a + b;
}
You can use the bind() method to create a new function with the first parameter (a) set.
var add5 = add.bind(null, 5);
Now the add5 function can be used like this -
<!doctype html>
<html>
<head>
<title>Examples</title>
</head>
<body>
<div id="result"></div>
<script>
function add(a, b) {
return a + b;
}
var add5 = add.bind(null, 5);
document.getElementById("result").innerHTML = add5(10)
</script>
</body>
</html>
As you can see, the first parameter (5) is set and the second parameter (10) is passed to the add5 function.
Method 2
Another way to use partial function application is to create a function that accepts an existing function and a value and returns a new function with the first argument of the existing function set.
For example, you can write a function like this -
function bind(fn, val) {
return function() {
return fn.apply(null,
[val].concat(Array.prototype.slice.call(arguments)));
};
}
This function accepts an existing function and a value and returns a new function whose value is bound to the first argument of the existing function.
For example, you can use the bind() function to create a new function like this -
var add5 = bind(add, 5);
Now the add5 function can be used like this -
<!doctype html>
<html>
<head>
<title>Examples</title>
</head>
<body>
<div id="result"></div>
<script>
function add(a, b) {
return a + b;
}
function bind(fn, val) {
return function() {
return fn.apply(null, [val].concat(Array.prototype.slice.call(arguments)));
};
}
var add5 = add.bind(add, 5);
document.getElementById("result").innerHTML = add5(10)
</script>
</body>
</html>
As you can see, the first parameter (5) is set and the second parameter (10) is passed to the add5 function.
Partial function application is a useful technique for creating new functions from existing functions. It can be used to create a function that is similar to an existing function, but with some parameters already set.
The above is the detailed content of How to call a function with a section appended to parameters in JavaScript?. For more information, please follow other related articles on the PHP Chinese website!
From Websites to Apps: The Diverse Applications of JavaScriptApr 22, 2025 am 12:02 AMJavaScript is widely used in websites, mobile applications, desktop applications and server-side programming. 1) In website development, JavaScript operates DOM together with HTML and CSS to achieve dynamic effects and supports frameworks such as jQuery and React. 2) Through ReactNative and Ionic, JavaScript is used to develop cross-platform mobile applications. 3) The Electron framework enables JavaScript to build desktop applications. 4) Node.js allows JavaScript to run on the server side and supports high concurrent requests.
Python vs. JavaScript: Use Cases and Applications ComparedApr 21, 2025 am 12:01 AMPython is more suitable for data science and automation, while JavaScript is more suitable for front-end and full-stack development. 1. Python performs well in data science and machine learning, using libraries such as NumPy and Pandas for data processing and modeling. 2. Python is concise and efficient in automation and scripting. 3. JavaScript is indispensable in front-end development and is used to build dynamic web pages and single-page applications. 4. JavaScript plays a role in back-end development through Node.js and supports full-stack development.
The Role of C/C in JavaScript Interpreters and CompilersApr 20, 2025 am 12:01 AMC and C play a vital role in the JavaScript engine, mainly used to implement interpreters and JIT compilers. 1) C is used to parse JavaScript source code and generate an abstract syntax tree. 2) C is responsible for generating and executing bytecode. 3) C implements the JIT compiler, optimizes and compiles hot-spot code at runtime, and significantly improves the execution efficiency of JavaScript.
JavaScript in Action: Real-World Examples and ProjectsApr 19, 2025 am 12:13 AMJavaScript's application in the real world includes front-end and back-end development. 1) Display front-end applications by building a TODO list application, involving DOM operations and event processing. 2) Build RESTfulAPI through Node.js and Express to demonstrate back-end applications.
JavaScript and the Web: Core Functionality and Use CasesApr 18, 2025 am 12:19 AMThe main uses of JavaScript in web development include client interaction, form verification and asynchronous communication. 1) Dynamic content update and user interaction through DOM operations; 2) Client verification is carried out before the user submits data to improve the user experience; 3) Refreshless communication with the server is achieved through AJAX technology.
Understanding the JavaScript Engine: Implementation DetailsApr 17, 2025 am 12:05 AMUnderstanding how JavaScript engine works internally is important to developers because it helps write more efficient code and understand performance bottlenecks and optimization strategies. 1) The engine's workflow includes three stages: parsing, compiling and execution; 2) During the execution process, the engine will perform dynamic optimization, such as inline cache and hidden classes; 3) Best practices include avoiding global variables, optimizing loops, using const and lets, and avoiding excessive use of closures.
Python vs. JavaScript: The Learning Curve and Ease of UseApr 16, 2025 am 12:12 AMPython is more suitable for beginners, with a smooth learning curve and concise syntax; JavaScript is suitable for front-end development, with a steep learning curve and flexible syntax. 1. Python syntax is intuitive and suitable for data science and back-end development. 2. JavaScript is flexible and widely used in front-end and server-side programming.
Python vs. JavaScript: Community, Libraries, and ResourcesApr 15, 2025 am 12:16 AMPython and JavaScript have their own advantages and disadvantages in terms of community, libraries and resources. 1) The Python community is friendly and suitable for beginners, but the front-end development resources are not as rich as JavaScript. 2) Python is powerful in data science and machine learning libraries, while JavaScript is better in front-end development libraries and frameworks. 3) Both have rich learning resources, but Python is suitable for starting with official documents, while JavaScript is better with MDNWebDocs. The choice should be based on project needs and personal interests.
Hot AI Tools
Undresser.AI Undress
AI-powered app for creating realistic nude photos
AI Clothes Remover
Online AI tool for removing clothes from photos.
Undress AI Tool
Undress images for free
Clothoff.io
AI clothes remover
Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!
Hot Article
Hot Tools
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.
WebStorm Mac version
Useful JavaScript development tools
Atom editor mac version download
The most popular open source editor
EditPlus Chinese cracked version
Small size, syntax highlighting, does not support code prompt function
DVWA
Damn Vulnerable Web App (DVWA) is a PHP/MySQL web application that is very vulnerable. Its main goals are to be an aid for security professionals to test their skills and tools in a legal environment, to help web developers better understand the process of securing web applications, and to help teachers/students teach/learn in a classroom environment Web application security. The goal of DVWA is to practice some of the most common web vulnerabilities through a simple and straightforward interface, with varying degrees of difficulty. Please note that this software
