Detailing Array

1-TimeComplixity.md

Operation	Time Complexity
Access	O(1)
Search	O(n)
Insertion	O(n)
Deletion	O(n)

2-ArrayCreation.md

Array Literal

The simplest way is to use the array literal [] and list the elements inside.

let myArray = [1, 2, 3, 4, 5];

---

Array Constructor

You can use the Array constructor to create an array. You can either provide the array size or list elements as arguments.

let myArray = new Array(1, 2, 3, 4, 5);

---

Empty Array with a Defined Length

You can create an empty array with a specific length using the Array constructor.

let emptyArray = new Array(5);
// Results in an array with five undefined elements: [undefined, undefined, undefined, undefined, undefined]

3-ArrayMethods.md

Static Methods

Array.from()

• Creates a new Array instance from an iterable or array-like object.

let newArray = Array.from('hello', char => char.toUpperCase());
// Results in ['H', 'E', 'L', 'L', 'O']

Array.isArray()

• Returns true if the argument is an array, or false otherwise.

console.log(Array.isArray([1, 2, 3])); // true
console.log(Array.isArray("hello"));   // false

Array.of()

• Creates a new Array instance with a variable number of arguments, regardless of number or type of the arguments.

let myArray = Array.of(1, 2, 3, 4, 5);

Array.fromAsync()

• Creates a new Array instance from an async iterable, iterable, or array-like object.

async function fetchUserData(userId) {
  // Simulate an asynchronous call
  const response = await fetch(`https://api.example.com/users/${userId}`);
  return response.json();
}

(async () => {
  const userIds = [1, 2, 3];

  const users = await Array.fromAsync(userIds, async (userId) => {
    const user = await fetchUserData(userId);
    return user.name;
  });

  console.log(users); // ["John Doe", "Jane Doe", "Alice Smith"]
})();

---

4-ArrayMethods.md

Instance Property

• These properties are defined on Array.prototype and shared by all Array instances

length

• Reflects the number of elements in an array.

  let array = [1, 2, 3, 4, 5];
  console.log(array.length); // Outputs 5

Instance Methods

at

• Returns the array item at the given index. Accepts negative integers, which count back from the last item.

const arr = [1, 2, 3, 4, 5];
let index = 2;
console.log(arr.at(index)); // Outputs 8

index = -2;
console.log(arr.at(index)); // Output 4

concat

• Concatenates (joins) arrays or values to the calling array and returns a new array.

  let arr1 = [1, 2, 3];
  let arr2 = [4, 5, 6];
  let concatenatedArray = arr1.concat(arr2); // Outputs [1, 2, 3, 4, 5, 6]

join

• Joins all elements of an array into a string, using the specified separator.

  let arr = ['apple', 'mango', 'orange'];
  console.log(arr.join(', '));  // Output: 'apple, mango, orange'
  console.log(arr.join('-'));  // Output: 'apple-mango-orange'

reverse

• Reverses the order of the elements of an array in place. (First becomes the last, last becomes first.)
• and returns the reference to the same array.

const array1 = ['one', 'two', 'three'];
array1.reverse();
console.log(array1); // ["three", "two", "one"]

[1, 2, 3, 4, 5].at(1); // 2
[1, 2, 3, 4, 5].pop(); // 5
[3, 4, 5, 61.push(7); // [3, 4, 5, 6, 7]
[3, 4, 5, 6].fill(1); // [1, 1, 1, 1]