Most Common JavaScript Array Methods

There are some common Javascript Array methods we use in JavaScript. In this article, I tried to highlight some of the common array methods I mostly used in JavaScript even in React projects.

I have provided the 16 most used JavaScript methods. I have also included code examples for easier understanding.

Let's Go!!!

length()

Returns the number of elements in an array.

const colors = ['red', 'green', 'blue'];
console.log(colors.length); 

Output:

3 

toString()

Converts the elements of an array into a string and returns the result.

const colors = ['red', 'green', 'blue'];
console.log(colors.toString()); 

Output:

"red,green,blue" 

indexOf()

Returns the first index at which a given element can be found in the array, or -1 if it is not present.

const colors = ['red', 'green', 'blue'];
console.log(colors.indexOf('green')); 

Output:

1 

pop()

Removes the last element from an array and returns that element.

const colors = ['red', 'green', 'blue'];
const removedColor = colors.pop();
console.log(removedColor); 

Output:

"blue"

push()

Adds one or more elements to the end of an array and returns the new length of the array.

const colors = ['red', 'green'];
const newLength = colors.push('blue');
console.log(colors); 

Output:

['red', 'green', 'blue']

concat()

Returns a new array that combines the original array's elements with other arrays or values.

const colors = ['red', 'green'];
const moreColors = colors.concat(['blue', 'yellow']);
console.log(moreColors); 

Output:

["red", "green", "blue", "yellow"]

slice()

Returns a shallow copy of a portion of an array into a new array object selected from start to end (end not included).

const colors = ['red', 'green', 'blue', 'yellow'];
const slicedColors = colors.slice(1, 3);
console.log(slicedColors);

Output:

["green", "blue"]

splice()

Changes the contents of an array by removing or replacing existing elements and/or adding new elements in place.

const colors = ['red', 'green', 'blue', 'yellow'];
colors.splice(2, 1, 'orange'); // Removes 1 element starting from index 2 and adds 'orange'
console.log(colors);

Output:

["red", "green", "orange", "yellow"] 

filter()

Creates a new array with all elements that pass the test implemented by the provided function.

const colors = ['red', 'green', 'blue', 'yellow'];
const filteredColors = colors.filter(color => color.length > 4);
console.log(filteredColors); 

Output:

["green", "yellow"] 

find()

Returns the value of the first element in the array that satisfies the provided testing function, or is undefined if no such element is found.

const colors = ['red', 'green', 'blue', 'yellow'];
const foundColor = colors.find(color => color === 'green');
console.log(foundColor); 

Output:

"green"

forEach()

Executes a provided function once for each array element.

const colors = ['red', 'green', 'blue'];
colors.forEach(color => console.log(color.toUpperCase()));

Output:

RED
GREEN
BLUE

includes()

Determines whether an array includes a certain element, returning true or false as appropriate.

const colors = ['red', 'green', 'blue'];
console.log(colors.includes('yellow')); 

Output:

false 

map()

Creates a new array populated with the results of calling a provided function on every element in the calling array.

const colors = ['red', 'green', 'blue'];
const capitalizedColors = colors.map(color => color.toUpperCase());
console.log(capitalizedColors);

Output:

["RED", "GREEN", "BLUE"]

reduce()

Executes a reducer function (that you provide) on each array element, resulting in a single output value.

const numbers = [1, 2, 3, 4, 5];
const sum = numbers.reduce((acc, curr) => acc + curr, 0);
console.log(sum); 

Output:

15

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