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JS Array Helper Method

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ES6 introduced powerful array iteration methods that make working with arrays simpler, cleaner, and more readable. These helper methods iterate over arrays and apply functions to their elements.


forEach:

Executes a provided function once for each array element. It does not return anything.

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

// Example: Logging each element
numbers.forEach((num) => {
console.log(num);
});
Try it yourself

map:

Creates a new array by applying a function to each element of the original array. It returns the transformed array.

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

// Example: Squaring each element
const squares = numbers.map((num) => num * num);
console.log(squares); // [1, 4, 9, 16, 25]
Try it yourself

find:

Returns the first element in the array that satisfies a specified condition. If no element matches, it returns undefined.

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

// Example: Finding the first even number
const firstEven = numbers.find((num) => num % 2 === 0);
console.log(firstEven); // 2
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findIndex:

Returns the index of the first element that satisfies a specified condition. If no element matches, it returns -1.

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

// Example: Finding the index of the first even number
const firstEvenIndex = numbers.findIndex((num) => num % 2 === 0);
console.log(firstEvenIndex); // 1
Try it yourself

filter:

Creates a new array containing elements that pass a specified condition (filter function). It returns the filtered array.

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

// Example: Filtering out even numbers
const evens = numbers.filter((num) => num % 2 === 0);
console.log(evens); // [2, 4]
Try it yourself

reduce:

Executes a reducer function on each element of the array, resulting in a single output value.

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

// Example: Summing up all elements
const sum = numbers.reduce((acc, num) => acc + num, 0);
console.log(sum); // 15
Try it yourself

some:

Checks if at least one element in the array satisfies a specified condition. Returns true or false.

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

// Example: Checking if the array contains any even numbers
const hasEven = numbers.some((num) => num % 2 === 0);
console.log(hasEven); // true
Try it yourself

every:

Checks if all elements in the array satisfy a specified condition. Returns true or false.

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

// Example: Checking if all elements are positive
const allPositive = numbers.every((num) => num > 0);
console.log(allPositive); // true
Try it yourself

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