Error Handling - Reference

Resilient Code, Predictable Errors

Learn to handle errors gracefully and build reliable systems with robust error-handling patterns.

1. Error Categories

Recoverable Errors

File not found, invalid input, API timeouts. Use try/catch blocks or Result() types.

Unrecoverable Errors

Memory access violations, deadlocks. Implemented as panic() or abort().

2. Propagation Strategies

Manual Propagation


function loadFile(path: String): Result {
    const file = try fs.open(path);
    return Result.ok(file.read());
}

Automatic Propagation


async function fetchUser(id: number): Promise {
    const response = await http.get(`/users/${id}`);
    if (!response.ok) Error.throw(`User ${id} not found`);
    return response.json();
}

3. Custom Error Objects

Add context to errors using custom types:


class AuthError extends SystemError {
    constructor() {
        super(401, 'Unauthorized access attempt');
        this.suggestion = 'Provide valid API credentials';
    }
}

<error type="AuthError">

{
"code": 401,
"message": "Unauthorized access attempt",
"suggestion": "Provide valid API credentials"
}

4. Error Visualization

Error Propagation Graph

• → ✳️ → ❌ ERROR

Stack Trace

at handleRequest (server.js:142:5)

at receive (router.js:41:3)

at parse (parser.js:17:41)