JavaScript - insert item into array at specific index

In this article, we would like to show you how to insert item into array at specific index using JavaScript.

Quick solution:

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var array = ['a', 'b', 'd'];

var index = 2;

var item = 'c';

​

array.splice(index, 0, item); // insert item at index (removing 0 items)

​

console.log(array); // [ 'a', 'b', 'c', 'd' ]

Note:

The second argument - 0 is the number of items to delete while inserting the item.

In this example, we extend the Array object by adding custom insert() method that accepts 2 arguments: index at which we want to insert the item, and the item.

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Array.prototype.insert = function(index, item) {

  this.splice(index, 0, item);

};

​

var array = ['a', 'b', 'd'];

​

array.insert(2, 'c');

​

console.log(array); // [ 'a', 'b', 'c', 'd' ]

1. Array.prototype.splice() - JavaScript | MDN