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Explain 'Not a constructor function' error in JavaScript?
The not a constructor function error occurs if we use an object or a variable as a constructor that isn’t a constructor.
Following is the code for not a constructor function error 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: rebeccapurple;
}
</style>
</head>
<body>
<h1>Not a constructor function error</h1>
<div class="result"></div>
<button class="Btn">CLICK HERE</button>
<h3>Click on the above button to use a variable as constructor</h3>
<script>
let resEle = document.querySelector(".result");
let BtnEle = document.querySelector(".Btn");
let b = 22;
BtnEle.addEventListener("click", () => {
try {
new b();
}
catch (err) {
resEle.innerHTML = err;
}
});
</script>
</body>
</html>
Output
The above code will produce the following output −

On clicking the ‘CLICK HERE’ button −

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