Express Error Handling

const express = require("express");
const app = express();

// ... সব routes ...

// সব route-এর পরে 404 handle — এই middleware শেষে রাখতে হবে
app.use((req, res) => {
  res.status(404).json({
    success: false,
    message: "এই route পাওয়া যায়নি",
    path: req.originalUrl,
  });
});

// Error handler middleware — শেষে রাখুন
app.use((err, req, res, next) => {
  const status = err.status || 500;
  const message = err.message || "Internal Server Error";

  console.error("❌", err);

  res.status(status).json({
    success: false,
    message,
    stack: process.env.NODE_ENV === "production" ? undefined : err.stack,
  });
});

class AppError extends Error {
  constructor(message, status = 500) {
    super(message);
    this.status = status;
    this.name = "AppError";
  }
}

module.exports = AppError;

const AppError = require("./utils/AppError");

// ❌ এটা error throw করলেও catch হবে না
app.get("/data", async (req, res, next) => {
  const data = await riskyFunction(); // reject হলে crash!
  res.json(data);
});

// ✅ async wrapper দিয়ে
const asyncHandler = (fn) => (req, res, next) => {
  Promise.resolve(fn(req, res, next)).catch(next);
};

app.get("/data", asyncHandler(async (req, res) => {
  const data = await riskyFunction();
  res.json(data);
}));

app.post("/users", async (req, res, next) => {
  try {
    const user = await createUser(req.body);
    res.status(201).json(user);
  } catch (error) {
    next(new AppError("User তৈরি করা যায়নি", 400));
  }
});