Swap Array Elements In JavaScript Using Array Prototype And Other Methods

In this tutorial, we will be using a function to swap array elements in JavaScript/jQuery. We will implement the same objective, using an Array.prototype.

 

Hence, let's start with the code.

 

Method 1

Check the code, mentioned below. Here, I have used jQuery version 3.1.0. Inside the $(document).ready() section, we have declared an array and a Swap() function to swap the array elements. We are passing the actual array and the indexes to this function.

<script src="https://code.jquery.com/jquery-3.1.0.js"></script>
<script type="text/javascript">

$(document).ready(function(){

var myArray = [18,3,90,25,2,27,36, 22, 4];  //Declare the array
var testString = '';  // declare a temporary variable to store the sorted array values.

//Declare the function to swap the array elements using a third variable.
//Here we are passing the array indexes as well as the array itself
function Swap(arr,a, b){
   var temp;
   temp = arr[a];
   arr[a] = arr[b];
   arr[b] = temp;
}

//Declare the function to sort the array
function Sort(array){
 for(var j = 0; j< array.length-1; j++){
     for(var k = 1; k< array.length; k++){
       if(array[k] < array[k - 1]){
        Swap(array,k,k-1)  //call the Swap function here
       }
     }
 }
}

//Call the Sort Function with the array declared above
Sort(myArray);

//Loop through the sorted array elements after swapping
for(var i = 0; i < myArray.length; i++){
  testString += ", " + myArray[i];
}

alert(testString.substring(2));  // Display the sorted array after swapping

});
</script>

Method 2

In this method, we will implement the Swap() function with the Array.prototype builtin. Check with the code, mentioned below. I have added Swap() function to Array.prototype.

 

P.S 

This method should be avoided while working with multiple JS library, as it may create confusion.

<script src="https://code.jquery.com/jquery-3.1.0.js"></script>
<script type="text/javascript">

$(document).ready(function(){

var myArray = [18,3,90,25,2,27,36, 22, 4];
var testString = '';

//Declare the Swap function with Array.prototype. We are only passing the indexes here.
Array.prototype.Swap = function (x,y) {
  var b = this[x];
  this[x] = this[y];
  this[y] = b;
  return this; // return the current array instance.
}


//Declare the sort function
function Sort(array){
 for(var j = 0; j< array.length-1; j++){
     for(var k = 1; k< array.length; k++){
       if(array[k] < array[k - 1]){
         array.Swap(k,k-1)  // Call the Swap() function like this.
       }
     }
 }
}

//call the Sort() function
Sort(myArray);

for(var i = 0; i < myArray.length; i++){
  testString += ", " + myArray[i];
}

alert(testString.substring(2)); // display the sorted array.

});
</script>

I hope, this will be helpful for the beginners in JavaScript. Please comment and provide the feedback, if you like my post. Thank you for reading.