Using closures to achieve privacy in JavaScript

JavascriptWeb DevelopmentObject Oriented Programming

Following is the code for implementing closures to achieve privacy in JavaScript −

Example

 Live Demo

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>Document</title>
<style>
   body {
      font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
   }
   .result {
      font-size: 18px;
      font-weight: 500;
      color: blueviolet;
   }
</style>
</head>
<body>
<h1>Using closures to achieve privacy</h1>
<div class="result"></div>
<br />
<button class="Btn">Increment</button>
<button class="Btn">Access</button>
<h3>Click on the above button to increment or try to access the variable</h3>
<script>
   let resEle = document.querySelector(".result");
   let BtnEle = document.querySelectorAll(".Btn");
   function increment() {
      let a = 0;
      return function () {
         a++;
         return a;
      };
   }
   let inc;
   inc = increment();
   BtnEle[0].addEventListener("click", () => {
      resEle.innerHTML = inc();
   });
   BtnEle[1].addEventListener("click", () => {
      try {
         resEle.innerHTML = a;
      } catch (err) {
         resEle.innerHTML = err;
      }
   });
</script>
</body>
</html>

Output

On clicking the ‘Increment’ button 4 times −

On clicking the ‘Access’ button −

raja
Published on 18-Jul-2020 11:46:38
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