JavaScript Program To Add Element To Start Of An Array - Programiz

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JavaScript Program to Add Element to Start of an Array

To understand this example, you should have the knowledge of the following JavaScript programming topics:

  • JavaScript Array unshift()
  • JavaScript Array splice()
  • JavaScript Array concat()

Example 1: Add Element to Array Using unshift()

// program to add element to an array function addElement(arr) { // adding new array element arr.unshift(4); console.log(arr); } const array = [1, 2, 3]; // calling the function // passing array argument addElement(array);

Output

[4, 1, 2, 3]

In the above program, the new element is added to the array variable using the unshift() method.

The unshift() method adds a new element at the beginning of an array.

Example 2: Add Element to Array Using splice()

// program to add element to an array function addElement(arr) { // adding element to array arr.splice(0, 0, 4); console.log(arr); } const array = [1, 2, 3]; // calling the function addElement(array);

Output

[4, 1, 2, 3]

In the above program, the splice() method is used to add a new element to an array.

In the splice() method,

  • The first argument is the index of an array where you want to add an element.
  • The second argument is the number of elements that you want to remove from the index element.
  • The third argument is the element that you want to add to the array.

Example 3: Add Element to Array Using Spread Operator

// program to add element to an array function addElement(arr) { // adding element to array arr = [4, ...arr]; console.log(arr); } const array = [1, 2, 3]; // calling the function addElement(arr);

Output

[4, 1, 2, 3]

In the above program, the spread operator ... is used to add a new element to the beginning of an array.

arr = [4, ...arr]; takes first element as 4 and the rest elements are taken from array.

Example 4: Add Element to Array Using concat()

// program to add element to an array function addElement(arr) { // adding element to array arr = [4].concat(arr); console.log(arr); } const array = [1, 2, 3]; // calling the function addElement(array);

Output

[4, 1, 2, 3]

In the above program, the concat() method is used to add a new element to an array.

The concat() method combines two arrays into one.

Also Read:

  • JavaScript Program to Insert Item in an Array
  • JavaScript Program to Append an Object to An Array

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