Day 12 of 30 of JavaScript

Introduction

Hey there! 😊 I hope you’re doing well. In our last post, we studied the searching and sorting methods used with arrays. Today, we’ll discuss iteration methods that are commonly used with arrays. Let’s get started! 🔥

Iteration Methods

Array iteration methods are functions or techniques that allow you to traverse through each element of an array systematically. These methods enable you to perform operations on each element without manually writing loops.

Array.forEach() Method

The forEach() method executes a provided callback function once for each array element.

const numbers = [1, 2, 3];
numbers.forEach((value, index) => {
    console.log(`Index: ${index}, Value: ${value}`);
});

The callback function can accept three arguments:

• value: The current element being processed.
• index: The index of the current element.
• array: The array that forEach() was called upon.

Array.map() Method

The map() method creates a new array populated with the results of calling a provided function on every element in the calling array.

const doubled = numbers.map(num => num * 2); // [2, 4, 6]

The callback function can also accept the same three arguments as forEach().

Array.filter() Method

The filter() method creates a new array with all elements that pass the test implemented by the provided function.

const evenNumbers = numbers.filter(num => num % 2 === 0); // [2]

Array.reduce() Method

The reduce() method executes a reducer function on each element of the array, resulting in a single output value. It processes the array from left to right.

const sum = numbers.reduce((accumulator, currentValue) => accumulator + currentValue, 0); // 6

There is also a reduceRight() method that works similarly but processes the array from right to left.

Array.every() Method

The every() method tests whether all elements in the array pass the test implemented by the provided function.

const allPositive = numbers.every(num => num > 0); // true

Array.some() Method

The some() method tests whether at least one element in the array passes the test implemented by the provided function.

const hasNegative = numbers.some(num => num < 0); // false

Array Spread Operator (...)

The spread operator (...) expands an iterable (like an array) into more elements. It provides a concise and flexible way to work with iterables, making your code more readable.

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

Conclusion

These iteration methods are essential tools in JavaScript and are commonly used for array manipulation. I hope you found this blog helpful! In the upcoming posts, we’ll dive into Object-Oriented Programming (OOP) concepts. Until then, stay connected, and don’t forget to follow me!