Array Methods

at()

The at() method returns an indexed element from an array.

const fruits = ["Banana", "Orange", "Apple", "Mango"];
let index = 2;
let fruit = fruits.at(index);
console.log(fruit);

concat()

The concat() helps in joining two arrays. You can also join three arrays eg: arr1.concat(arr2, arr3);

const arr1 = ["a", "b"];
const arr2 = ["c", "d", "e"];
const children = arr1.concat(arr2);
console.log(children);

copyWithin()

The copyWithin() method does the following:

• copies array elements to another position in an array.
• overwrites the existing values

const fruits = ["Banana", "Orange", "Apple", "Mango"];
fruits.copyWithin(2, 0);

console.log(fruits); // [ 'Banana', 'Orange', 'Banana', 'Orange' ]

entries()

The entries() method returns an array iterator object with key/value pairs. This method does not change the original array.

const fruits = ["Banana", "Orange", "Apple", "Mango"];
const f = fruits.entries();

for (const entry of f) {
    console.log(entry);
}

/* Output
[ 0, 'Banana' ]
[ 1, 'Orange' ]
[ 2, 'Apple' ]
[ 3, 'Mango' ]
*/