How Can I Insert Elements into JavaScript Arrays at Specific Indices?

Inserting Elements into Arrays at Specific Indices

JavaScript arrays naturally lack an intuitive insert method. However, a compelling solution exists through the native array function splice.

Using splice for Array Insertion

The splice function takes three arguments:

• index: The index at which to insert the new element.
• deleteCount: The number of elements to delete at the specified index (default 0).
• item: The element to insert.

To insert an element at a specific index, use the following syntax:

arr.splice(index, 0, item);

This inserts the item into the array at the index, without deleting any existing elements.

Code Example

Consider the following JavaScript code:

var arr = [];
arr[0] = "Jani";
arr[1] = "Hege";
arr[2] = "Stale";
arr[3] = "Kai Jim";
arr[4] = "Borge";

console.log(arr.join()); // Jani,Hege,Stale,Kai Jim,Borge
arr.splice(2, 0, "Lene");
console.log(arr.join()); // Jani,Hege,Lene,Stale,Kai Jim,Borge

In this example:

• We create an array arr with several elements.
• We splice the array at index 2, inserting the element "Lene" without deleting any existing elements.
• The resulting array is logged to the console, demonstrating the successful insertion of "Lene" at index 2.

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