</>
typescriptbeginner

Async Error Handler Wrapper

Higher-order function that wraps async Express route handlers and forwards rejected promises to error middleware.

typescript
import { Request, Response, NextFunction, RequestHandler } from 'express';

type AsyncHandler = (
  req: Request,
  res: Response,
  next: NextFunction
) => Promise<void>;

export const asyncHandler = (fn: AsyncHandler): RequestHandler => {
  return (req, res, next) => {
    Promise.resolve(fn(req, res, next)).catch(next);
  };
};

// Usage:
// app.get('/users/:id', asyncHandler(async (req, res) => {
//   const user = await db.users.findById(req.params.id);
//   if (!user) throw new NotFoundError('User not found');
//   res.json(user);
// }));

Use Cases

  • Express route error handling
  • Avoiding try-catch boilerplate
  • Centralized error management

Tags

#express#async#error-handling#middleware

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typescriptintermediate

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