Arrays vs Set in JavaScript.

The Set data type was introduced in ES2015 and the difference between array and set is that while an array can have duplicate values a set can’t. Elements can be accessed in array using index which isn’t possible in Set since it uses keys and elements can be traversed only in the way they were entered.

Following is the code displaying the difference between array and Set in JavaScript −


 Live Demo

<!DOCTYPE html>
<html lang="en">
<meta charset="UTF-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
   body {
      font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
   .result,.sample {
      font-size: 18px;
      font-weight: 500;
      color: rebeccapurple;
   .result {
      color: red;
<h1>Array Vs Set</h1>
<div class="sample"></div>
<div class="result"></div>
<button class="Btn">Convert</button>
<h3>Click on the above button to convert the above array into a set</h3>
   let resultEle = document.querySelector(".result");
   let sampleEle = document.querySelector(".sample");
   let arr = [2, 3, 4, 2, 3, 4, "A", "A", "B", "B"];
   sampleEle.innerHTML = "arr = " + arr;
   document.querySelector(".Btn").addEventListener("click", () => {
      let set1 = new Set(arr);
      resultEle.innerHTML = "set1 = " + [...set1] + "<br>";


The above code will produce the following output −

On clicking the ‘Convert’ button −

On clicking the ‘Display’ button −