JavaScript error can be extended by extending the error class. The best way to do this is to create a new custom error class that extends the built in JavaScript error class.
Following is the code for extending errors 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>Extend JavaScript Error</h1>
<div class="result"></div>
<button class="Btn">CLICK HERE</button>
<h3>
Click on the above button to create a new error by extending the error class
</h3>
<script>
let resEle = document.querySelector(".result");
let sampleEle = document.querySelector(".sample");
let BtnEle = document.querySelector(".Btn");
class CustomError extends Error {
constructor(message) {
super(message);
this.name = "Custom Error";
}
}
function test() {
throw new CustomError("New Error thrown");
}
BtnEle.addEventListener("click", () => {
try {
test();
}
catch (err) {
resEle.innerHTML += "err.name = " + err.name + "<br>";
resEle.innerHTML += "err.message = " + err.message + "<br>";
}
});
</script>
</body>
</html>Output
The above code will produce the following output −
On clicking the ‘CLICK HERE’ button −
