Js Error Handling — Free Javascript Tutorial

TL;DR: Learn Js Error Handling in Javascript with a free, beginner-friendly tutorial, examples and practice for Indian students on Syllab.in.

Js Error Handling in Javascript

JavaScript errors, if unhandled, crash the script and show confusing messages to users. Error handling with try/catch lets you gracefully manage failures and provide helpful feedback.

try block contains code that might fail. catch(error) runs if an error occurs — error.message gives the description, error.name gives the type, error.stack gives the call trace. finally runs regardless of success or failure.

Custom Error classes extend the built-in Error class, letting you create domain-specific errors with meaningful names (ValidationError, NetworkError, AuthError). This makes debugging much easier.

Promise rejection and async errors: for async/await code, wrap in try/catch. For .then() chains, add .catch(). Unhandled promise rejections in Node.js cause the process to crash.

try {
    // code that might throw
    const result = riskyOperation();
} catch (error) {
    console.error(error.message);  // what went wrong
    console.error(error.name);     // Error, TypeError, etc.
} finally {
    // always runs (cleanup)
    cleanup();
}

// Custom error:
class ValidationErr

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