JavaScript Core | VoidX Academy

13. Error Handling

Architecture

Error Handling

In production, APIs fail, networks drop, and users input bad data. A crashed app is a terrible user experience. Error handling allows you to catch these disasters gracefully.

🛡️ Try, Catch, Finally

You wrap dangerous code inside a try block. If it explodes, execution instantly jumps to the catch block without crashing the whole application.

try {
    // Attempting to call a function that doesn't exist
    fakeFunction();
    console.log("This line will never run.");

} catch (error) {
    // This intercepts the crash
    console.error("Caught an error!", error.message);

} finally {
    // This ALWAYS runs, crash or no crash. Used for cleanup.
    console.log("Execution complete.");
}

OutputCaught an error! fakeFunction is not defined
Execution complete.

⚡ Throwing Custom Errors

You can enforce business logic by manually triggering errors using the throw keyword.

function processPayment(amount) {
    if (amount <= 0) {
        throw new Error("Payment amount must be greater than zero.");
    }
    return `Processed $${amount}`;
}

try {
    console.log(processPayment(-5));
} catch (err) {
    console.error("Transaction Failed:", err.message);
}

OutputTransaction Failed: Payment amount must be greater than zero.

13. Error Handling

Error Handling

🛡️ Try, Catch, Finally

⚡ Throwing Custom Errors

Knowledge Check

13. Error Handling

Error Handling

🛡️ Try, Catch, Finally

⚡ Throwing Custom Errors

Knowledge Check