Example 1: Add Item to Array Using splice()
// program to insert an item at a specific index into an array
function insertElement() {
let array = [1, 2, 3, 4, 5];
// index to add to
let index = 3;
// element that you want to add
let element = 8;
array.splice(index, 0, element);
console.log(array);
}
insertElement();
Output
[1, 2, 3, 8, 4, 5]
In the above program, the splice()
method is used to insert an item with a specific index into an array.
The splice()
method adds and/or removes an item.
In the splice()
method,
- The first argument specifies the index where you want to insert an item.
- The second argument (here 0) specifies the number of items to remove.
- The third argument specifies the element that you want to add to an array.
Example 2: Add Item to Array Using for Loop
// program to insert an item at a specific index into an array
function insertElement() {
let array = [1, 2, 3, 4];
// index to add to
let index = 3;
// element that you want to add
let element = 8;
for (let i = array.length; i > index; i--) {
//shift the elements that are greater than index
array[i] = array[i-1];
}
// insert element at given index
array[index] = element;
console.log(array);
}
insertElement();
Output
[1, 2, 3, 8, 4]
In the above program,
- The
for
loop is used to iterate through the array elements. - The element is added to the given index.
- All the elements whose index is greater than the given index are shifted one step to the right.