Errors

Errors in JavaScript are objects that provide information about the type of error, the statement that caused the error, and the stack trace when the error occurred. JavaScript also allows programmers to create custom errors to provide extra information when debugging issues.

Types of Errors

Syntax Error: Occurs when there is a mistake in the syntax of the code.
Reference Error: Occurs when a non-existent variable is referenced.
Type Error: Occurs when a value is not of the expected type.
Range Error: Occurs when a value is not within the set or range of allowed values.
URI Error: Occurs when there is an error in encoding or decoding a URI.
Eval Error: Occurs when the eval() function is used incorrectly.
Internal Error: Occurs when an internal error in the JavaScript engine is thrown.

Handling Errors

JavaScript provides several mechanisms to handle errors:

Try...Catch

The try...catch statement allows you to test a block of code for errors and handle them gracefully.

try {
    // Code that may throw an error
    let result = someFunction();
} catch (error) {
    // Code to handle the error
    console.error(error.message);
}

Throw

The throw statement allows you to create a custom error.

function checkNumber(num) {
    if (num > 10) {
        throw new Error("Number is too large");
    }
    return num;
}

try {
    checkNumber(15);
} catch (error) {
    console.error(error.message); // Number is too large
}

Finally

The finally block lets you execute code after the try and catch blocks, regardless of the result.

try {
    // Code that may throw an error
    let result = someFunction();
} catch (error) {
    // Code to handle the error
    console.error(error.message);
} finally {
    // Code to be executed regardless of the result
    console.log("Execution completed");
}

Example :

<html>
<body>
<p id="result"></p>
<p id="error" class="error"></p>

<script>
function someFunction() {
// Simulate an error
throw new Error("From MyClass An unexpected error occurred!");
}

try {
// Code that may throw an error
let result = someFunction();
document.getElementById("result").innerHTML = "Function executed successfully: " + result;
} catch (error) {
// Code to handle the error
console.error(error.message);
document.getElementById("error").innerHTML = "Error: " + error.message;
}
</script>

</body>
</html>

For more detailed information, you can check out resources like W3Schools and MDN Web Docs.