1k-error-handling

# Error Handling

Best practices for error handling in OneKey codebase.

## Core Principles

- Use try/catch blocks for async operations that might fail
- Provide appropriate error messages and fallbacks
- Use `useAsyncCall` hook for operations needing loading/error states
- **Never swallow errors silently**

## Quick Reference

### Basic Try/Catch
```typescript
async function fetchData() {
  try {
    const result = await apiCall();
    return result;
  } catch (error) {
    console.error('Failed to fetch data:', error);
    throw error; // Re-throw if caller needs to handle
  }
}
```

### With Fallback Value
```typescript
async function fetchDataWithFallback() {
  try {
    const result = await apiCall();
    return result;
  } catch (error) {
    console.error('Failed to fetch, using fallback:', error);
    return defaultValue; // Return fallback instead of throwing
  }
}
```

### Using useAsyncCall Hook
```typescript
import { useAsyncCall } from '@onekeyhq/kit/src/hooks/useAsyncCall';

function MyComponent() {
  const { run, isLoading, error, result } = useAsyncCall(
    async () => {
      return await fetchData();
    },
    {
      onError: (e) => {
        Toast.error({ title: 'Failed to load data' });
      },
    }
  );

  if (error) {
    return <ErrorView error={error} onRetry={run} />;
  }

  return <DataView data={result} loading={isLoading} />;
}
```

### User-Facing Errors
```typescript
async function submitForm(data: FormData) {
  try {
    await api.submit(data);
    Toast.success({ title: 'Submitted successfully' });
  } catch (error) {
    // Show user-friendly message
    Toast.error({
      title: 'Submission failed',
      message: getUserFriendlyMessage(error),
    });
    // Log detailed error for debugging
    console.error('Form submission error:', error);
  }
}
```

## Anti-Patterns

### Silent Error Swallowing
```typescript
// ❌ BAD: Error silently ignored
async function badExample() {
  try {
    await riskyOperation();
  } catch (error) {
    // Nothing here - error lost forever
  }
}

// ✅ GOOD: At minimum, log the error
async function goodExample() {
  try {
    await riskyOperation();
  } catch (error) {
    console.error('Operation failed:', error);
    // Handle appropriately
  }
}
```

### Missing Error State in UI
```typescript
// ❌ BAD: No error state
function BadComponent() {
  const { data } = useQuery();
  return <View>{data}</View>; // What if data fetch fails?
}

// ✅ GOOD: Handle all states
function GoodComponent() {
  const { data, isLoading, error } = useQuery();

  if (isLoading) return <Loading />;
  if (error) return <Error error={error} />;
  return <View>{data}</View>;
}
```

## Detailed Guide

For comprehensive error handling patterns and examples, see [error-handling.md](references/rules/error-handling.md).

Topics covered:
- Core principles
- Error handling patterns (try/catch, fallbacks, hooks)
- Error boundaries for React
- Error types (network, validation, user-facing)
- Anti-patterns to avoid
- Error handling checklist

## Checklist

- [ ] All async operations wrapped in try/catch
- [ ] Errors logged for debugging
- [ ] User-friendly messages shown to users
- [ ] Loading and error states handled in UI
- [ ] No silent error swallowing
- [ ] Specific error types caught when appropriate

## Related Skills

- `/1k-coding-patterns` - General coding patterns and promise handling
- `/1k-sentry-analysis` - Sentry error analysis and fixes