Function returning another function in JavaScript

Javascript Web Development Object Oriented Programming

Following is the code wherein a function returns another function in JavaScript −

Example

<!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>Function returning another function in JavaScript</h1>
<div class="result"></div>
<button class="Btn">CLICK HERE</button>
<h3>Click on the above button to double the number</h3>
<script>
   let BtnEle = document.querySelector(".Btn");
   let resEle = document.querySelector(".result");
   function test() {
      let b = 1;
      return function () {
         resEle.innerHTML = "Number = " + (b *= 2);
      };
   }
   let returnFunc = test();
   BtnEle.addEventListener("click", () => {
      returnFunc();
   });
</script>
</body>
</html>