Web Front-end
JS Tutorial
How to call a function with a section appended to parameters in JavaScript?
How 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!
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
Notepad++7.3.1
Easy-to-use and free code editor
SublimeText3 Chinese version
Chinese version, very easy to use
Zend Studio 13.0.1
Powerful PHP integrated development environment
Dreamweaver CS6
Visual web development tools
SublimeText3 Mac version
God-level code editing software (SublimeText3)
Hot Topics
What should I do if I encounter garbled code printing for front-end thermal paper receipts?
Apr 04, 2025 pm 02:42 PM
Frequently Asked Questions and Solutions for Front-end Thermal Paper Ticket Printing In Front-end Development, Ticket Printing is a common requirement. However, many developers are implementing...
Demystifying JavaScript: What It Does and Why It Matters
Apr 09, 2025 am 12:07 AM
JavaScript is the cornerstone of modern web development, and its main functions include event-driven programming, dynamic content generation and asynchronous programming. 1) Event-driven programming allows web pages to change dynamically according to user operations. 2) Dynamic content generation allows page content to be adjusted according to conditions. 3) Asynchronous programming ensures that the user interface is not blocked. JavaScript is widely used in web interaction, single-page application and server-side development, greatly improving the flexibility of user experience and cross-platform development.
Who gets paid more Python or JavaScript?
Apr 04, 2025 am 12:09 AM
There is no absolute salary for Python and JavaScript developers, depending on skills and industry needs. 1. Python may be paid more in data science and machine learning. 2. JavaScript has great demand in front-end and full-stack development, and its salary is also considerable. 3. Influencing factors include experience, geographical location, company size and specific skills.
Is JavaScript hard to learn?
Apr 03, 2025 am 12:20 AM
Learning JavaScript is not difficult, but it is challenging. 1) Understand basic concepts such as variables, data types, functions, etc. 2) Master asynchronous programming and implement it through event loops. 3) Use DOM operations and Promise to handle asynchronous requests. 4) Avoid common mistakes and use debugging techniques. 5) Optimize performance and follow best practices.
How to achieve parallax scrolling and element animation effects, like Shiseido's official website?
or:
How can we achieve the animation effect accompanied by page scrolling like Shiseido's official website?
Apr 04, 2025 pm 05:36 PM
Discussion on the realization of parallax scrolling and element animation effects in this article will explore how to achieve similar to Shiseido official website (https://www.shiseido.co.jp/sb/wonderland/)...
How to merge array elements with the same ID into one object using JavaScript?
Apr 04, 2025 pm 05:09 PM
How to merge array elements with the same ID into one object in JavaScript? When processing data, we often encounter the need to have the same ID...
The Evolution of JavaScript: Current Trends and Future Prospects
Apr 10, 2025 am 09:33 AM
The latest trends in JavaScript include the rise of TypeScript, the popularity of modern frameworks and libraries, and the application of WebAssembly. Future prospects cover more powerful type systems, the development of server-side JavaScript, the expansion of artificial intelligence and machine learning, and the potential of IoT and edge computing.
The difference in console.log output result: Why are the two calls different?
Apr 04, 2025 pm 05:12 PM
In-depth discussion of the root causes of the difference in console.log output. This article will analyze the differences in the output results of console.log function in a piece of code and explain the reasons behind it. �...
