Interview question

How do you handle errors with async/await? async/await के साथ errors कैसे handle करें?

Answer

Errors in async/await are handled with standard try/catch blocks, unlike Promise chains which use .catch(). A rejected awaited Promise throws inside the try block.

async function fetchData() {
    try {
        const response = await fetch('/api/data');
        if (!response.ok) {
            throw new Error(`HTTP error: ${response.status}`);
        }
        const data = await response.json();
        return data;
    } catch (error) {
        console.log('Something went wrong:', error.message);
        return null; // fallback value
    } finally {
        console.log('Fetch attempt finished'); // always runs
    }
}

// Handling errors from multiple awaits individually
async function processOrder(orderId) {
    let order;
    try {
        order = await getOrder(orderId);
    } catch (error) {
        console.log('Could not fetch order:', error.message);
        return;
    }

    try {
        await processPayment(order);
    } catch (error) {
        console.log('Payment failed:', error.message);
        await refundIfNeeded(order);
    }
}

// Common mistake: forgetting try/catch causes unhandled rejection
async function risky() {
    const data = await fetch('/might-fail'); // if this rejects, function throws silently
    return data;
}
risky().catch(err => console.log('Caught outside:', err)); // still catchable via .catch() on the call

async/await में errors standard try/catch blocks से handle होते हैं, Promise chains की तरह .catch() से नहीं। Rejected awaited Promise try block के अंदर throw करता है।

async function fetchData() {
    try {
        const response = await fetch('/api/data');
        if (!response.ok) {
            throw new Error(`HTTP error: ${response.status}`);
        }
        const data = await response.json();
        return data;
    } catch (error) {
        console.log('कुछ गलत हुआ:', error.message);
        return null;
    } finally {
        console.log('Fetch attempt finished');
    }
}

async function processOrder(orderId) {
    let order;
    try {
        order = await getOrder(orderId);
    } catch (error) {
        console.log('Order fetch नहीं हुआ:', error.message);
        return;
    }

    try {
        await processPayment(order);
    } catch (error) {
        console.log('Payment fail हुआ:', error.message);
    }
}

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