Functions are very useful features in any programming language. Developers may be able to find any programming language that does not contain this function. Furthermore, when we start learning any programming language, we definitely learn about functions, i.e., blocks of code that provide reusability of the code.
In this tutorial, we will learn about higher-order functions and currying.
Higher-order functions
Before we start currying in JavaScript, let’s first understand higher-order functions.
The simple definition of a higher-order function is: a function that takes another function as a parameter or returns a function. Have you ever used the sort() method in JavaScript or any other programming language like C or Python? If so, you may have passed a callback function as argument to the sort() method to sort the array based on a specific context.
Therefore, we can say that the sort() method is a higher-order function.
grammar
Users can use higher-order functions according to the following syntax.
function sortArray(ele1, ele2) {
// function body
}
array.sort(sortArray);
In the above syntax, sort() is a higher-order function because we have passed the sortArray() function as a parameter.
Example
In the example below, we create an array of numbers containing different values. After that, we use the filter() method to filter out all elements in the array that are divisible by 2.
Users can observe that we have passed the filter_func() function as a parameter to the filter() method. Therefore, we can say that the filter() method is a higher-order function.
<html>
<body>
<h2 id="Higher-order-functions-using-the-filter-method">Higher-order functions using the filter() method.</h2>
<p id = "output"> </p>
<script>
let output = document.getElementById("output");
let array = [10, 30, 23, 32, 32, 32, 32, 45, 5, 6, 878989, 34, 23];
// creating the function to filter values
function filter_func(element) {
return element % 2 == 0;
}
// higher-order function
let divisibleBy2 = array.filter(filter_func);
output.innerHTML += "The filtered values are " + divisibleBy2;
</script>
</body>
</html>
Example
In this example, we create an array of strings. After that, we capitalize the first letter of all array values using the map() method. We pass the callback arrow function as an argument to the map method, which returns a string after the first character is capitalized.
We use the substr() and toUpperCase() methods to uppercase the first character of each array string.
<html>
<body>
<h2 id="Higher-order-functions-using-the-map-method">Higher-order functions using the map() method</h2>
<p id = "output"> </p>
<script>
let output = document.getElementById("output");
let array = ["hi", "users", "welcome", "on", "tutorialspoint!"];
output.innerHTML += "Original Array: <br>" + array + "<br>";
// higher-order function
let results = array.map((string) => {
// creating the first character capitalize
return string.substr(0, 1).toUpperCase() + string.substr(1);
});
output.innerHTML += "<br>The array after capitalizing the first character: <br>" + results;
</script>
</body>
</html>
Now, users can know the benefits of using higher-order functions. For example, the filter() method has been implemented in JavaScript’s Array library, allowing users to override filter logic by passing a custom callback function as a parameter.
Currying in JavaScript
Currying is similar to higher-order functions, it returns functions. Curried functions accept multiple parameters, and users can pass the parameter values to nested functions.
The last nested function of the curried function returns the final output.
grammar
Users can write curried functions according to the following syntax.
function addition(num1) {
return function (num2) {
return num1 + num2;
};
}
addition(10)(20);
We return this function from the addition() function in the above syntax. Additionally, users can also observe how we call the addition() function by passing multiple arguments.
Example
In the example below, we create a curried function named addition(). The addition function has only one parameter. It also returns a nested function that also takes a single argument. The nested function returns the sum of the num1 and num2 arguments.
<html>
<body>
<h2 id="Curried-functions">Curried functions</h2>
<p id = "output"> </p>
<script>
let output = document.getElementById("output");
// curried function, which returns the function
function addition(num1) {
return function (num2) {
return num1 + num2;
};
}
output.innerHTML += "After calling the curried function, the result is " + addition(10)(20);
</script>
</body>
</html>
Users learned about higher-order functions and curried functions in this tutorial. Higher-order and currying functions have many uses, some of which we've seen with three examples.
The above is the detailed content of Higher-order functions and currying in JavaScript. For more information, please follow other related articles on the PHP Chinese website!
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.
From C/C to JavaScript: How It All WorksApr 14, 2025 am 12:05 AMThe shift from C/C to JavaScript requires adapting to dynamic typing, garbage collection and asynchronous programming. 1) C/C is a statically typed language that requires manual memory management, while JavaScript is dynamically typed and garbage collection is automatically processed. 2) C/C needs to be compiled into machine code, while JavaScript is an interpreted language. 3) JavaScript introduces concepts such as closures, prototype chains and Promise, which enhances flexibility and asynchronous programming capabilities.
JavaScript Engines: Comparing ImplementationsApr 13, 2025 am 12:05 AMDifferent JavaScript engines have different effects when parsing and executing JavaScript code, because the implementation principles and optimization strategies of each engine differ. 1. Lexical analysis: convert source code into lexical unit. 2. Grammar analysis: Generate an abstract syntax tree. 3. Optimization and compilation: Generate machine code through the JIT compiler. 4. Execute: Run the machine code. V8 engine optimizes through instant compilation and hidden class, SpiderMonkey uses a type inference system, resulting in different performance performance on the same code.
Beyond the Browser: JavaScript in the Real WorldApr 12, 2025 am 12:06 AMJavaScript's applications in the real world include server-side programming, mobile application development and Internet of Things control: 1. Server-side programming is realized through Node.js, suitable for high concurrent request processing. 2. Mobile application development is carried out through ReactNative and supports cross-platform deployment. 3. Used for IoT device control through Johnny-Five library, suitable for hardware interaction.
Building a Multi-Tenant SaaS Application with Next.js (Backend Integration)Apr 11, 2025 am 08:23 AMI built a functional multi-tenant SaaS application (an EdTech app) with your everyday tech tool and you can do the same. First, what’s a multi-tenant SaaS application? Multi-tenant SaaS applications let you serve multiple customers from a sing
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
AI Hentai Generator
Generate AI Hentai for free.
Hot Article
Hot Tools
MinGW - Minimalist GNU for Windows
This project is in the process of being migrated to osdn.net/projects/mingw, you can continue to follow us there. MinGW: A native Windows port of the GNU Compiler Collection (GCC), freely distributable import libraries and header files for building native Windows applications; includes extensions to the MSVC runtime to support C99 functionality. All MinGW software can run on 64-bit Windows platforms.
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
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.
SublimeText3 Mac version
God-level code editing software (SublimeText3)
Notepad++7.3.1
Easy-to-use and free code editor
