Home Web Front-end JS Tutorial How to use foreach loop in js

How to use foreach loop in js

May 06, 2024 pm 01:54 PM

JavaScript forEach() loop is used to iterate over array elements. Syntax: array.forEach(callback(currentValue, index, array)). Usage steps: 1. Define the array; 2. Call the forEach() method and pass in the callback function; 3. Process the elements in the callback function. Advantages: easy to understand, powerful and efficient.

How to use foreach loop in js

Usage of JavaScript forEach() loop

Introduction
forEach() A loop is a built-in function in JavaScript for iterating over the elements of an array. It accepts a callback function as argument, which is called on each element in the array.

Syntax

array.forEach(callback(currentValue, index, array));
Copy after login

Where:

  • array is the array to be traversed.
  • callback is a function called on each element of the array and accepts three parameters:

    • currentValue : The element currently being processed.
    • index: The index of the current element in the array.
    • array: The array being traversed.

Usage
To use a forEach() loop, follow these steps:

  1. Define an array.
  2. Call the forEach() method and pass the callback function as a parameter.
  3. In the callback function, perform the required processing on each element.

Example

const numbers = [1, 2, 3, 4, 5];

// 打印每个数字
numbers.forEach((num) => {
  console.log(num);
});

// 计算数组中数字的总和
let sum = 0;
numbers.forEach((num) => {
  sum += num;
});
console.log(`总和:${sum}`);
Copy after login

Advantages

  • Easy to understand:forEach The syntax of () loop is simple to understand and easy to use.
  • Powerful functions: It provides powerful functions to access array elements and their indexes, allowing various operations to be performed.
  • Efficient: The forEach() loop is the best choice for traversing an array because it can efficiently access one element at a time.

Note

  • forEach() loop cannot modify the original array. To modify an array, use the map() or filter() method.
  • forEach() loop cannot interrupt the traversal. If you need to break the traversal, use the break statement or explicitly return false.

The above is the detailed content of How to use foreach loop in js. For more information, please follow other related articles on the PHP Chinese website!

Statement of this Website
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

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

Video Face Swap

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Tools

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

What should I do if I encounter garbled code printing for front-end thermal paper receipts? 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 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? 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.

How to merge array elements with the same ID into one object using JavaScript? 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...

Is JavaScript hard to learn? 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? 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/)...

The difference in console.log output result: Why are the two calls different? 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. �...

The Evolution of JavaScript: Current Trends and Future Prospects 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.

See all articles