Add an element to array in JavaScript

The following snippets allows you to add an element to array in JavaScript.

NOTE: Methods with (*) are mutating.

Method 1: Using push()*

let myArray = [1, 2, 3, 4]
myArray.push(5)

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

Adds an element to the end of the array and mutates itself.

Method 2: Using concat()

let myArray = [1, 2, 3, 4]
myArray = myArray.concat(5)

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

Adds an element to the end of the array and returns a new array.

Method 3: Using length

let myArray = [1, 2, 3, 4]
myArray[myArray.length] = 5

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

Adds an element to the end of the array using the next index of the last element.

Method 4: Using unshift()*

let myArray = [1, 2, 3, 4]
myArray.unshift(5)

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

Adds an element to the start of the array and mutates itself.

Method 5: Using splice()*

let myArray = [1, 2, 3, 4]
myArray.splice(myArray.length, 0, 5)

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

Adds an element at a specific index. In this example, we used the length of the array as the index to add an element at the end of the array.

let myArray = [1, 2, 3, 4]
myArray.splice(0, 0, 5)

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

Adds an element at a specific index. In this example, we used 0 as the index to add an element at the start of the array.

let myArray = [1, 2, 3, 4]
myArray.splice(1, 0, 5)

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

Adds an element at a specific index. In this example, we used 1 as the index.

Method 6: Using the spread operator

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

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

Adds an element to the end of the array and returns a new array.

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

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

Adds an element to the start of the array and returns a new array.

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