Common Array Methods in JavaScript

In this article we will see basic array methods used in our day-to-day programming.

1) array.push():

The push() method adds a new element to an array at the end.

Example:

var arrayPush = [1, 4, 5];

arrayPush.push(7); // [1,4,5,7]

2) array.pop():

The pop() method removes the last element from an array.

Example:

var arrayPop = [1, 4, 5, 7];

arrayPop.pop(); // [1,4,5]

3) array.sort():

The sort() method sorts an array alphabetically.

Example:

var arraySort = [“B”, “K”, “A”, “C”];

arraySort.sort(); // [A,B,C,K]

4) array.reverse():

The reverse() method reverses the elements in an array.

Example:

var arrayTest = [“B”, “K”, “A”, “C”];

arrayTest.sort(); // [A, B, C, K]

arrayTest.reverse(); // [K, C, B, A]

5) array.splice()

array.splice() method returns the removed item(s) in an array.

array.splice() method changes the original array.

array.splice() method can take n number of arguments

Example :

var array=[1,2,3,4,5];
console.log(array.splice(2)); // [3,4,5]

This will return [3,4,5]. The original array is affected resulting in array being [1,2].

//splice
var array=[1,2,3,4,5];
console.log(array.splice(2)); // [3,4,5]

console.log(array); // [1,2]

6) array.slice():

array.slice() method returns the selected element(s) in an array.

array.slice() method doesn’t change the original array.

array.slice() method takes 2 arguments.

Example:

var array=[1,2,3,4,5]
console.log(array.slice(2)); // [3,4,5]

This will return [3,4,5]. The original array is NOT affected with resulting in array being [1,2,3,4,5].

//slice
var array2=[1,2,3,4,5]
console.log(array2.slice(2)); // [3,4,5]

console.log(array2); // [1,2,3,4,5]

6) array.shift():

The array.shift() method removes the first element from an array and returns that removed element. Length of the array will be modified.

Example:

const array1 = [1, 2, 3];

const test = array1.shift();

console.log(array1); // [2, 3]

console.log(test); // [1]

7) array.unshift():

The array.unshift() method adds one or more elements to the beginning of an array and returns the new array.

Example:

const test = [1, 2, 3];

console.log(test.unshift(4, 5)); // [5]

console.log(test); // [4, 5, 1, 2, 3]

8) array.indexOf():

The array.indexOf() method returns the first index at which a given element can be found in the array. It returns -1 if it is not present.

Example:

const test = [‘a’, ‘b’, ‘c’, ‘d’, ‘b’];

console.log(test.indexOf(‘b’)); // 1

console.log(test.indexOf(‘b’, 2)); // 4

console.log(test.indexOf(‘z’)); // -1

9) array.length():

The length property of an object which is an instance of type Array sets or returns the number of elements in that array.

Example:

const test = [‘a’, ‘b’, ‘c’, ‘d’];

console.log(test.length); // 4

10) array.filter():

The array.filter() method returns a new array with all elements that pass the test implemented by the provided function.

Example:

const test = [‘abc’, ‘xyz’, ‘qwerty’, ‘xyzabc’, ‘jkl’, ‘zxc’];

const result = test.filter(word => word.length > 4);

console.log(result); // Array [“qwerty”, “xyzabc”]

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Pranam Bhat

Pranam Bhat

Techie by brains and a traveler by heart :)