Arrays are fundamental data structures in JavaScript for storing ordered collections of items.

Method 1: Array Literal (Recommended)

The most common and preferred way:

// Empty array
const emptyArray = [];

// Array with items
const fruits = ["apple", "banana", "cherry"];
const numbers = [1, 2, 3, 4, 5];
const mixed = [1, "hello", true, null];

console.log(fruits); // ["apple", "banana", "cherry"]

Method 2: Array Constructor

Using the Array constructor:

// Empty array with specific length
const arr = new Array(5);
console.log(arr.length); // 5

// Array with items
const colors = new Array("red", "green", "blue");
console.log(colors); // ["red", "green", "blue"]

Method 3: Array.of()

Creates an array from arguments:

const nums = Array.of(1, 2, 3);
console.log(nums); // [1, 2, 3]

// Useful for single number (unlike Array constructor)
const single = Array.of(5);
console.log(single); // [5] (not an empty array of length 5)

Method 4: Array.from()

Create arrays from iterables or array-like objects:

// From a string
const chars = Array.from("hello");
console.log(chars); // ["h", "e", "l", "l", "o"]

// With a mapping function
const squares = Array.from([1, 2, 3], x => x * x);
console.log(squares); // [1, 4, 9]

// Create a range
const range = Array.from({length: 5}, (_, i) => i);
console.log(range); // [0, 1, 2, 3, 4]

Method 5: Spread Operator

Copy or combine arrays:

const original = [1, 2, 3];
const copy = [...original];

const combined = [...[1, 2], ...[3, 4]];
console.log(combined); // [1, 2, 3, 4]

Method 6: fill()

Create an array filled with a value:

const zeros = new Array(5).fill(0);
console.log(zeros); // [0, 0, 0, 0, 0]

const repeated = new Array(3).fill("hello");
console.log(repeated); // ["hello", "hello", "hello"]

Summary

Use [] array literals for most cases
Use Array.from() to convert iterables or create ranges
Use Array.of() when you need predictable behavior with single values
Use fill() to initialize arrays with a specific value

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