Array: Insert an Item at a Specific Index with JavaScript

There are many tasks related to arrays that sound quite simple but (1) aren't and (2) aren't required of a developer very often. I was encountered with one such task recently: inserting an item into an existing array at a specific index. Sounds easy and common enough but it took some research to figure it out.

// The original array
var array = ["one", "two", "four"];
// splice(position, numberOfItemsToRemove, item)
array.splice(2, 0, "three");

array;  // ["one", "two", "three", "four"]

If you aren't adverse to extending natives in JavaScript, you could add this method to the Array prototype:

Array.prototype.insert = function (index, item) {
  this.splice(index, 0, item);
};

I've tinkered around quite a bit with arrays, as you may have noticed:

• Remove an Item From an Array
• Clone Arrays
• Empty Arrays
• Sort Arrays

Arrays are super useful -- JavaScript just makes some tasks a bit more ... code-heavy than they need to be. Keep these snippets in your toolbox for the future!