Javascript - Insert at any index in an array

There is no straightforward API to insert in an array at any index in Javascript. Through splice API, it can be simulated as:

// extending the Array
Array.prototype.insert = function(i, e) {
  this.splice(i, 0, e)
}

In action

a = [2]

// insert 1 at 0th position
a.insert(0, 1)

// insert 3 at 2th position
a.insert(2, 3)

// insert 5 at 5th position
// wil it be error -> run it?
a.insert(5, 5)

Repl it

Check out script.js file.