2. [Arrays:](./docs/arrays.md)

- [Array methods](./docs/arrays.md#-array-methods)

- [Array iteration](./docs/arrays.md#-array-iteration)

Arrays are generally [Non-Primitive Data Types](./data-types.md#-non-primitive-data-types).

Array in JavaScript are collections of value list, where the values are any data type. They represent list of values.

1. [Array Methods](#-array-methods)

2. [Array Iteration](#-array-iteration)

JavaScript provide a variety of methods for manipulating and working with arrays.

**Common Array Methods:**

- `push():` Adds elements to the end of an array.

- `pop():` Removes the last element from an array and returns it.

- `shift():` Removes the first element from an array and returns it.

- `unshift():` Adds elements to the beginning of an array.  

- `slice():` Creates a new array containing a portion of the original array.

- `splice():` Removes or replaces elements in an array.

- `concat():` Combines multiple arrays into a new array.

- `join():` Joins elements of an array into a string.

- `reverse():` Reverses the order of elements in an array.

- `sort():` Sorts elements in an array.

- `forEach():` Executes a function for each element in an array.

- `map():` Creates a new array by applying a function to each element of the original array.

- `filter():` Creates a new array containing elements that meet a certain condition.

- `reduce():` Applies a function to each element in an array to reduce it to a single value.

- `indexOf():` Returns the index of the first occurrence of an element in an array.

- `lastIndexOf():` Returns the index of the last occurrence of an element in an array.

- `includes():` Checks if an array contains a specified element.

- `find():` Returns the first element in an array that meets a certain condition.

- `findIndex():` Returns the index of the first element in an array that meets a certain condition.

let fruits = ["apple", "banana", "orange"];

fruits.push("grape");

fruits.unshift("mango");

console.log(fruits); // Output: (5) ['mango', 'apple', 'banana', 'orange', 'grape']

let removedFruit = fruits.pop();

console.log(removedFruit); // Output: grape

console.log(fruits); // Output: (4) ['mango', 'apple', 'banana', 'orange']

let slicedFruits = fruits.slice(1, 3);

console.log(slicedFruits); // Output: (2) ['apple', 'banana']

console.log(fruits); // Output: (4) ['mango', 'apple', 'banana', 'orange']

let fruitString = fruits.join(", ");

console.log(fruitString); // Output: mango, apple, banana, orange

console.log(fruits); // Output: (4) ['mango', 'apple', 'banana', 'orange']

fruits.sort();

console.log(fruits); // Output: (4) ['apple', 'banana', 'mango', 'orange']

fruits.forEach(function(fruit) {

console.log(fruit);

});

let fruitLengths = fruits.map(function(fruit) {

return fruit.length;

});

console.log(fruitLengths); // Output: (4) [5, 6, 5, 6]

Array iteration involves traversing each element of an array to perform operations on them. There are several ways to iterate over arrays in JavaScript.

**Iteration of Array:**

- for loop:

for (let i = 0; i < fruits.length; i++) {

console.log(fruits[i]);

}

- for...in loop:

for (let index in fruits) {

console.log(fruits[index]);

}

- for...of loop:

for (let fruit of fruits) {

console.log(fruit);

}

- Array methods as loop:

- forEach()

- map()

- filter()

- reduce()

*These methods provide different ways to iterate over arrays and perform operations on their elements, depending on the specific needs.*

**Note:** When comes to loop, iterations, setTimeout and setInterval. Use [`let`](./variables.md#-let). That treats as a new [`variable`](./variables.md) on each iteration. But [`var`](./variables.md#-var) overwrites that memory place.

let fruits = ["apple", "banana", "orange"];

for(let fruit of fruits) {

setTimeout(() => { console.log(fruit) }, 1000);

}

let fruits = ["apple", "banana", "orange"];

for(var fruit of fruits) {

setTimeout(() => { console.log(fruit) }, 1000);

}

[&#8682; To Top](#-arrays)

[&#10094; Previous Topic](./objects.md) &emsp; [Next Topic &#10095;](./asynchronous-javascript.md)

[&#8962; Goto Home Page](../README.md)